diff --git a/docs/calendar.md b/docs/calendar.md
index 846897755b..4642500c2a 100644
--- a/docs/calendar.md
+++ b/docs/calendar.md
@@ -97,6 +97,15 @@ Your object must not have a `calendar` property, so that it can be distinguished
 
 The identifier of a custom calendar must consist of one or more components of between 3 and 8 ASCII alphanumeric characters each, separated by dashes, as described in [Unicode Technical Standard 35](https://unicode.org/reports/tr35/tr35.html#Unicode_locale_identifier).
 
+Custom calendars are responsible for interpreting and validating all inputs, including options.
+Calendars should (and built-in calendars will) throw a TypeError if a required option is missing or has the wrong type, but throw a RangeError if it's present but has an invalid value.
+
+Calendars are also responsible for assigning default values.
+For example, if the `overflow` option is undefined, it will be interpreted by built-in calendars as `'constrain'`.
+Custom calendars should maintain this behavior unless there's a good reason not to.
+Calendars can also accept additional non-default values for existing options or can accept new options that built-in calendars don't.
+When adding new options, calendar authors should use a unique prefix, e.g. the name of the calendar, to avoid potential conflicts with future options which may be used by Temporal.
+
 ## Constructor
 
 ### **new Temporal.Calendar**(_calendarIdentifier_: string) : Temporal.Calendar
@@ -346,12 +355,15 @@ date.toString(); // => 2020-06-28[u-ca-islamic]
 If either of `one` or `two` are not `Temporal.PlainDate` objects, then they will be converted to one as if they were passed to `Temporal.PlainDate.from()`.
 
 This method does not need to be called directly except in specialized code.
-It is called indirectly when using the `until()` and `since()` methods of `Temporal.PlainDateTime`, `Temporal.PlainDate`, and `Temporal.PlainYearMonth`.
+It is called indirectly when using the `until()` and `since()` methods of `Temporal.PlainDateTime`, `Temporal.PlainDate`, `Temporal.PlainYearMonth`, and `Temporal.ZonedDateTime`.
 
 If `one` is later than `two`, then the resulting duration should be negative.
 
 The default `largestUnit` value of `'auto'` is the same as `'days'`.
 
+> **NOTE:** Unlike `Temporal.Calendar.dateAdd()`, the `options` object that this method receives is not always the same object passed to the respective `until()` or `since()` method.
+> Depending on the type, a copy may be made of the object.
+
 For example:
 
 ```javascript
diff --git a/polyfill/lib/ecmascript.mjs b/polyfill/lib/ecmascript.mjs
index 66c9acffde..f41c75696c 100644
--- a/polyfill/lib/ecmascript.mjs
+++ b/polyfill/lib/ecmascript.mjs
@@ -842,7 +842,7 @@ export const ES = ObjectAssign({}, ES2020, {
         millisecond,
         microsecond,
         nanosecond
-      } = ES.InterpretTemporalDateTimeFields(calendar, fields, 'constrain'));
+      } = ES.InterpretTemporalDateTimeFields(calendar, fields, { overflow: 'constrain' }));
       offset = relativeTo.offset;
       timeZone = relativeTo.timeZone;
     } else {
@@ -1077,7 +1077,7 @@ export const ES = ObjectAssign({}, ES2020, {
     return ES.ToRecord(bag, entries);
   },
 
-  ToTemporalDate: (item, constructor, overflow = 'constrain') => {
+  ToTemporalDate: (item, constructor, options = {}) => {
     if (ES.Type(item) === 'Object') {
       if (ES.IsTemporalDate(item)) return item;
       let calendar = item.calendar;
@@ -1085,8 +1085,9 @@ export const ES = ObjectAssign({}, ES2020, {
       calendar = ES.ToTemporalCalendar(calendar);
       const fieldNames = ES.CalendarFields(calendar, ['day', 'month', 'year']);
       const fields = ES.ToTemporalDateFields(item, fieldNames);
-      return ES.DateFromFields(calendar, fields, constructor, overflow);
+      return ES.DateFromFields(calendar, fields, constructor, options);
     }
+    ES.ToTemporalOverflow(options); // validate and ignore
     let { year, month, day, calendar } = ES.ParseTemporalDateString(ES.ToString(item));
     ES.RejectDate(year, month, day);
     if (calendar === undefined) calendar = ES.GetISO8601Calendar();
@@ -1095,13 +1096,14 @@ export const ES = ObjectAssign({}, ES2020, {
     if (!ES.IsTemporalDate(result)) throw new TypeError('invalid result');
     return result;
   },
-  InterpretTemporalDateTimeFields: (calendar, fields, overflow) => {
+  InterpretTemporalDateTimeFields: (calendar, fields, options) => {
     const TemporalDate = GetIntrinsic('%Temporal.PlainDate%');
-    const date = ES.DateFromFields(calendar, fields, TemporalDate, overflow);
+    const date = ES.DateFromFields(calendar, fields, TemporalDate, options);
     const year = GetSlot(date, ISO_YEAR);
     const month = GetSlot(date, ISO_MONTH);
     const day = GetSlot(date, ISO_DAY);
     let { hour, minute, second, millisecond, microsecond, nanosecond } = ES.ToTemporalTimeRecord(fields);
+    const overflow = ES.ToTemporalOverflow(options);
     ({ hour, minute, second, millisecond, microsecond, nanosecond } = ES.RegulateTime(
       hour,
       minute,
@@ -1113,7 +1115,7 @@ export const ES = ObjectAssign({}, ES2020, {
     ));
     return { year, month, day, hour, minute, second, millisecond, microsecond, nanosecond };
   },
-  ToTemporalDateTime: (item, constructor, overflow = 'constrain') => {
+  ToTemporalDateTime: (item, constructor, options = {}) => {
     let year, month, day, hour, minute, second, millisecond, microsecond, nanosecond, calendar;
     if (ES.Type(item) === 'Object') {
       if (ES.IsTemporalDateTime(item)) return item;
@@ -1134,8 +1136,9 @@ export const ES = ObjectAssign({}, ES2020, {
         millisecond,
         microsecond,
         nanosecond
-      } = ES.InterpretTemporalDateTimeFields(calendar, fields, overflow));
+      } = ES.InterpretTemporalDateTimeFields(calendar, fields, options));
     } else {
+      ES.ToTemporalOverflow(options); // validate and ignore
       ({
         year,
         month,
@@ -1219,7 +1222,7 @@ export const ES = ObjectAssign({}, ES2020, {
     if (!ES.IsTemporalInstant(result)) throw new TypeError('invalid result');
     return result;
   },
-  ToTemporalMonthDay: (item, constructor, overflow = 'constrain') => {
+  ToTemporalMonthDay: (item, constructor, options = {}) => {
     if (ES.Type(item) === 'Object') {
       if (ES.IsTemporalMonthDay(item)) return item;
       let calendar = item.calendar;
@@ -1227,9 +1230,10 @@ export const ES = ObjectAssign({}, ES2020, {
       calendar = ES.ToTemporalCalendar(calendar);
       const fieldNames = ES.CalendarFields(calendar, ['day', 'month']);
       const fields = ES.ToTemporalMonthDayFields(item, fieldNames);
-      return ES.MonthDayFromFields(calendar, fields, constructor, overflow);
+      return ES.MonthDayFromFields(calendar, fields, constructor, options);
     }
 
+    ES.ToTemporalOverflow(options); // validate and ignore
     let { month, day, referenceISOYear = 1972, calendar } = ES.ParseTemporalMonthDayString(ES.ToString(item));
     ES.RejectDate(referenceISOYear, month, day);
     if (calendar === undefined) calendar = ES.GetISO8601Calendar();
@@ -1273,7 +1277,7 @@ export const ES = ObjectAssign({}, ES2020, {
     if (!ES.IsTemporalTime(result)) throw new TypeError('invalid result');
     return result;
   },
-  ToTemporalYearMonth: (item, constructor, overflow = 'constrain') => {
+  ToTemporalYearMonth: (item, constructor, options = {}) => {
     if (ES.Type(item) === 'Object') {
       if (ES.IsTemporalYearMonth(item)) return item;
       let calendar = item.calendar;
@@ -1281,9 +1285,10 @@ export const ES = ObjectAssign({}, ES2020, {
       calendar = ES.ToTemporalCalendar(calendar);
       const fieldNames = ES.CalendarFields(calendar, ['month', 'year']);
       const fields = ES.ToTemporalYearMonthFields(item, fieldNames);
-      return ES.YearMonthFromFields(calendar, fields, constructor, overflow);
+      return ES.YearMonthFromFields(calendar, fields, constructor, options);
     }
 
+    ES.ToTemporalOverflow(options); // validate and ignore
     let { year, month, referenceISODay = 1, calendar } = ES.ParseTemporalYearMonthString(ES.ToString(item));
     ES.RejectDate(year, month, referenceISODay);
     if (calendar === undefined) calendar = ES.GetISO8601Calendar();
@@ -1355,13 +1360,7 @@ export const ES = ObjectAssign({}, ES2020, {
     const instant = ES.GetTemporalInstantFor(timeZone, dt, disambiguation);
     return GetSlot(instant, EPOCHNANOSECONDS);
   },
-  ToTemporalZonedDateTime: (
-    item,
-    constructor,
-    overflow = 'constrain',
-    disambiguation = 'compatible',
-    offsetOpt = 'reject'
-  ) => {
+  ToTemporalZonedDateTime: (item, constructor, options = {}) => {
     let year, month, day, hour, minute, second, millisecond, microsecond, nanosecond, timeZone, offset, calendar;
     if (ES.Type(item) === 'Object') {
       if (ES.IsTemporalZonedDateTime(item)) return item;
@@ -1380,11 +1379,12 @@ export const ES = ObjectAssign({}, ES2020, {
         millisecond,
         microsecond,
         nanosecond
-      } = ES.InterpretTemporalDateTimeFields(calendar, fields, overflow));
+      } = ES.InterpretTemporalDateTimeFields(calendar, fields, options));
       timeZone = ES.ToTemporalTimeZone(fields.timeZone);
       offset = fields.offset;
       if (offset !== undefined) offset = ES.ToString(offset);
     } else {
+      ES.ToTemporalOverflow(options); // validate and ignore
       let ianaName;
       ({
         year,
@@ -1407,6 +1407,8 @@ export const ES = ObjectAssign({}, ES2020, {
     }
     let offsetNs = null;
     if (offset) offsetNs = ES.ParseOffsetString(offset);
+    const disambiguation = ES.ToTemporalDisambiguation(options);
+    const offsetOpt = ES.ToTemporalOffset(options, 'reject');
     const epochNanoseconds = ES.InterpretTemporalZonedDateTimeOffset(
       year,
       month,
@@ -1482,18 +1484,18 @@ export const ES = ObjectAssign({}, ES2020, {
       throw new RangeError('irreconcilable calendars');
     }
   },
-  DateFromFields: (calendar, fields, constructor, overflow = 'constrain') => {
-    const result = calendar.dateFromFields(fields, { overflow }, constructor);
+  DateFromFields: (calendar, fields, constructor, options) => {
+    const result = calendar.dateFromFields(fields, options, constructor);
     if (!ES.IsTemporalDate(result)) throw new TypeError('invalid result');
     return result;
   },
-  YearMonthFromFields: (calendar, fields, constructor, overflow = 'constrain') => {
-    const result = calendar.yearMonthFromFields(fields, { overflow }, constructor);
+  YearMonthFromFields: (calendar, fields, constructor, options) => {
+    const result = calendar.yearMonthFromFields(fields, options, constructor);
     if (!ES.IsTemporalYearMonth(result)) throw new TypeError('invalid result');
     return result;
   },
-  MonthDayFromFields: (calendar, fields, constructor, overflow = 'constrain') => {
-    const result = calendar.monthDayFromFields(fields, { overflow }, constructor);
+  MonthDayFromFields: (calendar, fields, constructor, options) => {
+    const result = calendar.monthDayFromFields(fields, options, constructor);
     if (!ES.IsTemporalMonthDay(result)) throw new TypeError('invalid result');
     return result;
   },
@@ -2115,7 +2117,7 @@ export const ES = ObjectAssign({}, ES2020, {
       calendar,
       'days'
     );
-    let intermediateNs = ES.AddZonedDateTime(start, timeZone, calendar, 0, 0, 0, days, 0, 0, 0, 0, 0, 0, 'constrain');
+    let intermediateNs = ES.AddZonedDateTime(start, timeZone, calendar, 0, 0, 0, days, 0, 0, 0, 0, 0, 0);
     // may disambiguate
 
     // If clock time after addition was in the middle of a skipped period, the
@@ -2129,7 +2131,7 @@ export const ES = ObjectAssign({}, ES2020, {
     if (sign === 1) {
       while (days > 0 && intermediateNs.greater(endNs)) {
         --days;
-        intermediateNs = ES.AddZonedDateTime(start, timeZone, calendar, 0, 0, 0, days, 0, 0, 0, 0, 0, 0, 'constrain');
+        intermediateNs = ES.AddZonedDateTime(start, timeZone, calendar, 0, 0, 0, days, 0, 0, 0, 0, 0, 0);
         // may do disambiguation
       }
     }
@@ -2139,22 +2141,7 @@ export const ES = ObjectAssign({}, ES2020, {
     let relativeInstant = new TemporalInstant(intermediateNs);
     do {
       // calculate length of the next day (day that contains the time remainder)
-      const oneDayFartherNs = ES.AddZonedDateTime(
-        relativeInstant,
-        timeZone,
-        calendar,
-        0,
-        0,
-        0,
-        sign,
-        0,
-        0,
-        0,
-        0,
-        0,
-        0,
-        'constrain'
-      );
+      const oneDayFartherNs = ES.AddZonedDateTime(relativeInstant, timeZone, calendar, 0, 0, 0, sign, 0, 0, 0, 0, 0, 0);
       const relativeNs = GetSlot(relativeInstant, EPOCHNANOSECONDS);
       dayLengthNs = oneDayFartherNs.subtract(relativeNs).toJSNumber();
       isOverflow = nanoseconds.subtract(dayLengthNs).multiply(sign).geq(0);
@@ -2191,8 +2178,7 @@ export const ES = ObjectAssign({}, ES2020, {
         seconds,
         milliseconds,
         microseconds,
-        nanoseconds,
-        'constrain'
+        nanoseconds
       );
       const startNs = GetSlot(relativeTo, EPOCHNANOSECONDS);
       nanoseconds = endNs.subtract(startNs);
@@ -2437,7 +2423,7 @@ export const ES = ObjectAssign({}, ES2020, {
       const timeZone = GetSlot(relativeTo, TIME_ZONE);
       const calendar = GetSlot(relativeTo, CALENDAR);
       const offsetBefore = ES.GetOffsetNanosecondsFor(timeZone, instant);
-      const after = ES.AddZonedDateTime(instant, timeZone, calendar, y, mon, w, d, h, min, s, ms, µs, ns, 'constrain');
+      const after = ES.AddZonedDateTime(instant, timeZone, calendar, y, mon, w, d, h, min, s, ms, µs, ns);
       const TemporalInstant = GetIntrinsic('%Temporal.Instant%');
       const instantAfter = new TemporalInstant(after);
       const offsetAfter = ES.GetOffsetNanosecondsFor(timeZone, instantAfter);
@@ -2711,7 +2697,8 @@ export const ES = ObjectAssign({}, ES2020, {
     µs2,
     ns2,
     calendar,
-    largestUnit
+    largestUnit,
+    options = {}
   ) => {
     const TemporalDate = GetIntrinsic('%Temporal.PlainDate%');
     let { deltaDays, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = ES.DifferenceTime(
@@ -2732,7 +2719,8 @@ export const ES = ObjectAssign({}, ES2020, {
     const date1 = new TemporalDate(y1, mon1, d1, calendar);
     const date2 = new TemporalDate(y2, mon2, d2, calendar);
     const dateLargestUnit = ES.LargerOfTwoTemporalDurationUnits('days', largestUnit);
-    let { years, months, weeks, days } = calendar.dateUntil(date1, date2, { largestUnit: dateLargestUnit });
+    const untilOptions = { ...options, largestUnit: dateLargestUnit };
+    let { years, months, weeks, days } = calendar.dateUntil(date1, date2, untilOptions);
     // Signs of date part and time part may not agree; balance them together
     ({ days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = ES.BalanceDuration(
       days,
@@ -2746,7 +2734,7 @@ export const ES = ObjectAssign({}, ES2020, {
     ));
     return { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds };
   },
-  DifferenceZonedDateTime: (ns1, ns2, timeZone, calendar, largestUnit) => {
+  DifferenceZonedDateTime: (ns1, ns2, timeZone, calendar, largestUnit, options) => {
     const nsDiff = ns2.subtract(ns1);
     if (nsDiff.isZero()) {
       return {
@@ -2789,24 +2777,11 @@ export const ES = ObjectAssign({}, ES2020, {
       GetSlot(dtEnd, ISO_MICROSECOND),
       GetSlot(dtEnd, ISO_NANOSECOND),
       calendar,
-      largestUnit
+      largestUnit,
+      options
     );
-    let intermediateNs = ES.AddZonedDateTime(
-      start,
-      timeZone,
-      calendar,
-      years,
-      months,
-      weeks,
-      0,
-      0,
-      0,
-      0,
-      0,
-      0,
-      0,
-      'constrain'
-    ); // may disambiguate
+    let intermediateNs = ES.AddZonedDateTime(start, timeZone, calendar, years, months, weeks, 0, 0, 0, 0, 0, 0, 0);
+    // may disambiguate
     let timeRemainderNs = ns2.subtract(intermediateNs);
     const TemporalZonedDateTime = GetIntrinsic('%Temporal.ZonedDateTime%');
     const intermediate = new TemporalZonedDateTime(intermediateNs, timeZone, calendar);
@@ -2967,8 +2942,7 @@ export const ES = ObjectAssign({}, ES2020, {
         s1,
         ms1,
         µs1,
-        ns1,
-        'constrain'
+        ns1
       );
       const endNs = ES.AddZonedDateTime(
         new TemporalInstant(intermediateNs),
@@ -2983,8 +2957,7 @@ export const ES = ObjectAssign({}, ES2020, {
         s2,
         ms2,
         µs2,
-        ns2,
-        'constrain'
+        ns2
       );
       if (largestUnit !== 'years' && largestUnit !== 'months' && largestUnit !== 'weeks' && largestUnit !== 'days') {
         // The user is only asking for a time difference, so return difference of instants.
@@ -3062,7 +3035,7 @@ export const ES = ObjectAssign({}, ES2020, {
     milliseconds,
     microseconds,
     nanoseconds,
-    overflow
+    options
   ) => {
     // Add the time part
     let deltaDays = 0;
@@ -3087,7 +3060,7 @@ export const ES = ObjectAssign({}, ES2020, {
     const TemporalDuration = GetIntrinsic('%Temporal.Duration%');
     const datePart = new TemporalDate(year, month, day, calendar);
     const dateDuration = new TemporalDuration(years, months, weeks, days, 0, 0, 0, 0, 0, 0);
-    const addedDate = calendar.dateAdd(datePart, dateDuration, { overflow }, TemporalDate);
+    const addedDate = calendar.dateAdd(datePart, dateDuration, options, TemporalDate);
 
     return {
       year: GetSlot(addedDate, ISO_YEAR),
@@ -3101,7 +3074,7 @@ export const ES = ObjectAssign({}, ES2020, {
       nanosecond
     };
   },
-  AddZonedDateTime: (instant, timeZone, calendar, years, months, weeks, days, h, min, s, ms, µs, ns, overflow) => {
+  AddZonedDateTime: (instant, timeZone, calendar, years, months, weeks, days, h, min, s, ms, µs, ns, options) => {
     // If only time is to be added, then use Instant math. It's not OK to fall
     // through to the date/time code below because compatible disambiguation in
     // the PlainDateTime=>Instant conversion will change the offset of any
@@ -3119,7 +3092,7 @@ export const ES = ObjectAssign({}, ES2020, {
     let dt = ES.GetTemporalDateTimeFor(timeZone, instant, calendar);
     const TemporalDate = GetIntrinsic('%Temporal.PlainDate%');
     const datePart = new TemporalDate(GetSlot(dt, ISO_YEAR), GetSlot(dt, ISO_MONTH), GetSlot(dt, ISO_DAY), calendar);
-    const addedDate = calendar.dateAdd(datePart, { years, months, weeks, days }, { overflow }, TemporalDate);
+    const addedDate = calendar.dateAdd(datePart, { years, months, weeks, days }, options, TemporalDate);
     const TemporalDateTime = GetIntrinsic('%Temporal.PlainDateTime%');
     const dtIntermediate = new TemporalDateTime(
       GetSlot(addedDate, ISO_YEAR),
@@ -3299,8 +3272,7 @@ export const ES = ObjectAssign({}, ES2020, {
       0,
       0,
       0,
-      0,
-      'constrain'
+      0
     );
     const TemporalZonedDateTime = GetIntrinsic('%Temporal.ZonedDateTime%');
     return new TemporalZonedDateTime(intermediateNs, timeZone, calendar);
@@ -3367,8 +3339,7 @@ export const ES = ObjectAssign({}, ES2020, {
       0,
       0,
       0,
-      0,
-      'constrain'
+      0
     );
     const TemporalInstant = GetIntrinsic('%Temporal.Instant%');
     const dayEnd = ES.AddZonedDateTime(
@@ -3384,8 +3355,7 @@ export const ES = ObjectAssign({}, ES2020, {
       0,
       0,
       0,
-      0,
-      'constrain'
+      0
     );
     const dayLengthNs = dayEnd.subtract(dayStart);
 
diff --git a/polyfill/lib/plaindate.mjs b/polyfill/lib/plaindate.mjs
index 56cb379eb5..9c5c8e29e8 100644
--- a/polyfill/lib/plaindate.mjs
+++ b/polyfill/lib/plaindate.mjs
@@ -135,10 +135,9 @@ export class PlainDate {
     fields = ES.CalendarMergeFields(calendar, fields, props);
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
 
     const Construct = ES.SpeciesConstructor(this, PlainDate);
-    return ES.DateFromFields(calendar, fields, Construct, overflow);
+    return ES.DateFromFields(calendar, fields, Construct, options);
   }
   withCalendar(calendar) {
     if (!ES.IsTemporalDate(this)) throw new TypeError('invalid receiver');
@@ -150,7 +149,10 @@ export class PlainDate {
   }
   add(temporalDurationLike, options = undefined) {
     if (!ES.IsTemporalDate(this)) throw new TypeError('invalid receiver');
+
     let duration = ES.ToLimitedTemporalDuration(temporalDurationLike);
+    options = ES.NormalizeOptionsObject(options);
+
     let { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     ({ days } = ES.BalanceDuration(days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds, 'days'));
@@ -162,7 +164,10 @@ export class PlainDate {
   }
   subtract(temporalDurationLike, options = undefined) {
     if (!ES.IsTemporalDate(this)) throw new TypeError('invalid receiver');
+
     let duration = ES.ToLimitedTemporalDuration(temporalDurationLike);
+    options = ES.NormalizeOptionsObject(options);
+
     let { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     ({ days } = ES.BalanceDuration(days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds, 'days'));
@@ -192,7 +197,7 @@ export class PlainDate {
     const roundingMode = ES.ToTemporalRoundingMode(options, 'trunc');
     const roundingIncrement = ES.ToTemporalRoundingIncrement(options, undefined, false);
 
-    const result = calendar.dateUntil(this, other, { largestUnit });
+    const result = calendar.dateUntil(this, other, options);
     if (smallestUnit === 'days' && roundingIncrement === 1) return result;
 
     let { years, months, weeks, days } = result;
@@ -249,7 +254,7 @@ export class PlainDate {
     const roundingMode = ES.ToTemporalRoundingMode(options, 'trunc');
     const roundingIncrement = ES.ToTemporalRoundingIncrement(options, undefined, false);
 
-    let { years, months, weeks, days } = calendar.dateUntil(this, other, { largestUnit });
+    let { years, months, weeks, days } = calendar.dateUntil(this, other, options);
     const Duration = GetIntrinsic('%Temporal.Duration%');
     if (smallestUnit === 'days' && roundingIncrement === 1) {
       return new Duration(-years, -months, -weeks, -days, 0, 0, 0, 0, 0, 0);
@@ -414,8 +419,8 @@ export class PlainDate {
   }
   static from(item, options = undefined) {
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     if (ES.IsTemporalDate(item)) {
+      ES.ToTemporalOverflow(options); // validate and ignore
       const year = GetSlot(item, ISO_YEAR);
       const month = GetSlot(item, ISO_MONTH);
       const day = GetSlot(item, ISO_DAY);
@@ -424,7 +429,7 @@ export class PlainDate {
       if (!ES.IsTemporalDate(result)) throw new TypeError('invalid result');
       return result;
     }
-    return ES.ToTemporalDate(item, this, overflow);
+    return ES.ToTemporalDate(item, this, options);
   }
   static compare(one, two) {
     one = ES.ToTemporalDate(one, PlainDate);
diff --git a/polyfill/lib/plaindatetime.mjs b/polyfill/lib/plaindatetime.mjs
index ce13bf964f..e473676a03 100644
--- a/polyfill/lib/plaindatetime.mjs
+++ b/polyfill/lib/plaindatetime.mjs
@@ -205,7 +205,6 @@ export class PlainDateTime {
     }
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const calendar = GetSlot(this, CALENDAR);
     const fieldNames = ES.CalendarFields(calendar, [
       'day',
@@ -234,7 +233,7 @@ export class PlainDateTime {
       millisecond,
       microsecond,
       nanosecond
-    } = ES.InterpretTemporalDateTimeFields(calendar, fields, overflow);
+    } = ES.InterpretTemporalDateTimeFields(calendar, fields, options);
 
     const Construct = ES.SpeciesConstructor(this, PlainDateTime);
     const result = new Construct(
@@ -317,7 +316,6 @@ export class PlainDateTime {
     let { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const calendar = GetSlot(this, CALENDAR);
     const { year, month, day, hour, minute, second, millisecond, microsecond, nanosecond } = ES.AddDateTime(
       GetSlot(this, ISO_YEAR),
@@ -340,7 +338,7 @@ export class PlainDateTime {
       milliseconds,
       microseconds,
       nanoseconds,
-      overflow
+      options
     );
     const Construct = ES.SpeciesConstructor(this, PlainDateTime);
     const result = new Construct(
@@ -364,7 +362,6 @@ export class PlainDateTime {
     let { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const calendar = GetSlot(this, CALENDAR);
     const { year, month, day, hour, minute, second, millisecond, microsecond, nanosecond } = ES.AddDateTime(
       GetSlot(this, ISO_YEAR),
@@ -387,7 +384,7 @@ export class PlainDateTime {
       -milliseconds,
       -microseconds,
       -nanoseconds,
-      overflow
+      options
     );
     const Construct = ES.SpeciesConstructor(this, PlainDateTime);
     const result = new Construct(
@@ -454,7 +451,8 @@ export class PlainDateTime {
       GetSlot(other, ISO_MICROSECOND),
       GetSlot(other, ISO_NANOSECOND),
       calendar,
-      largestUnit
+      largestUnit,
+      options
     );
 
     ({
@@ -547,7 +545,8 @@ export class PlainDateTime {
       GetSlot(other, ISO_MICROSECOND),
       GetSlot(other, ISO_NANOSECOND),
       calendar,
-      largestUnit
+      largestUnit,
+      options
     );
 
     ({
@@ -750,8 +749,8 @@ export class PlainDateTime {
 
   static from(item, options = undefined) {
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     if (ES.IsTemporalDateTime(item)) {
+      ES.ToTemporalOverflow(options); // validate and ignore
       const year = GetSlot(item, ISO_YEAR);
       const month = GetSlot(item, ISO_MONTH);
       const day = GetSlot(item, ISO_DAY);
@@ -766,7 +765,7 @@ export class PlainDateTime {
       if (!ES.IsTemporalDateTime(result)) throw new TypeError('invalid result');
       return result;
     }
-    return ES.ToTemporalDateTime(item, this, overflow);
+    return ES.ToTemporalDateTime(item, this, options);
   }
   static compare(one, two) {
     one = ES.ToTemporalDateTime(one, PlainDateTime);
diff --git a/polyfill/lib/plainmonthday.mjs b/polyfill/lib/plainmonthday.mjs
index 566e72aa49..1ec78ebfac 100644
--- a/polyfill/lib/plainmonthday.mjs
+++ b/polyfill/lib/plainmonthday.mjs
@@ -90,10 +90,9 @@ export class PlainMonthDay {
     fields = ES.CalendarMergeFields(calendar, fields, props);
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
 
     const Construct = ES.SpeciesConstructor(this, PlainMonthDay);
-    const result = ES.MonthDayFromFields(calendar, fields, Construct, overflow);
+    const result = ES.MonthDayFromFields(calendar, fields, Construct, options);
     if (!ES.IsTemporalMonthDay(result)) throw new TypeError('invalid result');
     return result;
   }
@@ -155,8 +154,8 @@ export class PlainMonthDay {
   }
   static from(item, options = undefined) {
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     if (ES.IsTemporalMonthDay(item)) {
+      ES.ToTemporalOverflow(options); // validate and ignore
       const month = GetSlot(item, ISO_MONTH);
       const day = GetSlot(item, ISO_DAY);
       const calendar = GetSlot(item, CALENDAR);
@@ -165,7 +164,7 @@ export class PlainMonthDay {
       if (!ES.IsTemporalMonthDay(result)) throw new TypeError('invalid result');
       return result;
     }
-    return ES.ToTemporalMonthDay(item, this, overflow);
+    return ES.ToTemporalMonthDay(item, this, options);
   }
 }
 
diff --git a/polyfill/lib/plainyearmonth.mjs b/polyfill/lib/plainyearmonth.mjs
index d42c9473c1..7c84097966 100644
--- a/polyfill/lib/plainyearmonth.mjs
+++ b/polyfill/lib/plainyearmonth.mjs
@@ -107,10 +107,9 @@ export class PlainYearMonth {
     fields = ES.CalendarMergeFields(calendar, fields, props);
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
 
     const Construct = ES.SpeciesConstructor(this, PlainYearMonth);
-    return ES.YearMonthFromFields(calendar, fields, Construct, overflow);
+    return ES.YearMonthFromFields(calendar, fields, Construct, options);
   }
   add(temporalDurationLike, options = undefined) {
     if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
@@ -120,7 +119,6 @@ export class PlainYearMonth {
     ({ days } = ES.BalanceDuration(days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds, 'days'));
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
 
     const TemporalDate = GetIntrinsic('%Temporal.PlainDate%');
     const calendar = GetSlot(this, CALENDAR);
@@ -133,7 +131,7 @@ export class PlainYearMonth {
     const addedDateFields = ES.ToTemporalYearMonthFields(addedDate, fieldNames);
 
     const Construct = ES.SpeciesConstructor(this, PlainYearMonth);
-    return ES.YearMonthFromFields(calendar, addedDateFields, Construct, overflow);
+    return ES.YearMonthFromFields(calendar, addedDateFields, Construct, options);
   }
   subtract(temporalDurationLike, options = undefined) {
     if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
@@ -155,7 +153,6 @@ export class PlainYearMonth {
     ({ days } = ES.BalanceDuration(days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds, 'days'));
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
 
     const TemporalDate = GetIntrinsic('%Temporal.PlainDate%');
     const calendar = GetSlot(this, CALENDAR);
@@ -168,7 +165,7 @@ export class PlainYearMonth {
     const addedDateFields = ES.ToTemporalYearMonthFields(addedDate, fieldNames);
 
     const Construct = ES.SpeciesConstructor(this, PlainYearMonth);
-    return ES.YearMonthFromFields(calendar, addedDateFields, Construct, overflow);
+    return ES.YearMonthFromFields(calendar, addedDateFields, Construct, options);
   }
   until(other, options = undefined) {
     if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
@@ -206,7 +203,8 @@ export class PlainYearMonth {
     const otherDate = ES.DateFromFields(calendar, { ...otherFields, day: 1 }, TemporalDate);
     const thisDate = ES.DateFromFields(calendar, { ...thisFields, day: 1 }, TemporalDate);
 
-    const result = calendar.dateUntil(thisDate, otherDate, { largestUnit });
+    const untilOptions = { ...options, largestUnit };
+    const result = calendar.dateUntil(thisDate, otherDate, untilOptions);
     if (smallestUnit === 'months' && roundingIncrement === 1) return result;
 
     let { years, months } = result;
@@ -279,7 +277,8 @@ export class PlainYearMonth {
     const otherDate = ES.DateFromFields(calendar, { ...otherFields, day: 1 }, TemporalDate);
     const thisDate = ES.DateFromFields(calendar, { ...thisFields, day: 1 }, TemporalDate);
 
-    let { years, months } = calendar.dateUntil(thisDate, otherDate, { largestUnit });
+    const untilOptions = { ...options, largestUnit };
+    let { years, months } = calendar.dateUntil(thisDate, otherDate, untilOptions);
     const Duration = GetIntrinsic('%Temporal.Duration%');
     if (smallestUnit === 'months' && roundingIncrement === 1) {
       return new Duration(-years, -months, 0, 0, 0, 0, 0, 0, 0, 0);
@@ -361,7 +360,7 @@ export class PlainYearMonth {
     ObjectAssign(fields, ES.ToRecord(item, entries));
 
     const Date = GetIntrinsic('%Temporal.PlainDate%');
-    return ES.DateFromFields(calendar, fields, Date, 'reject');
+    return ES.DateFromFields(calendar, fields, Date, { overflow: 'reject' });
   }
   getISOFields() {
     if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');
@@ -374,8 +373,8 @@ export class PlainYearMonth {
   }
   static from(item, options = undefined) {
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     if (ES.IsTemporalYearMonth(item)) {
+      ES.ToTemporalOverflow(options); // validate and ignore
       const year = GetSlot(item, ISO_YEAR);
       const month = GetSlot(item, ISO_MONTH);
       const calendar = GetSlot(item, CALENDAR);
@@ -384,7 +383,7 @@ export class PlainYearMonth {
       if (!ES.IsTemporalYearMonth(result)) throw new TypeError('invalid result');
       return result;
     }
-    return ES.ToTemporalYearMonth(item, this, overflow);
+    return ES.ToTemporalYearMonth(item, this, options);
   }
   static compare(one, two) {
     one = ES.ToTemporalYearMonth(one, PlainYearMonth);
diff --git a/polyfill/lib/zoneddatetime.mjs b/polyfill/lib/zoneddatetime.mjs
index a573d91167..a0200f324e 100644
--- a/polyfill/lib/zoneddatetime.mjs
+++ b/polyfill/lib/zoneddatetime.mjs
@@ -194,7 +194,6 @@ export class ZonedDateTime {
     }
 
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const disambiguation = ES.ToTemporalDisambiguation(options);
     const offset = ES.ToTemporalOffset(options, 'prefer');
 
@@ -228,7 +227,7 @@ export class ZonedDateTime {
       millisecond,
       microsecond,
       nanosecond
-    } = ES.InterpretTemporalDateTimeFields(calendar, fields, overflow);
+    } = ES.InterpretTemporalDateTimeFields(calendar, fields, options);
     const offsetNs = ES.ParseOffsetString(fields.offset);
     const epochNanoseconds = ES.InterpretTemporalZonedDateTimeOffset(
       year,
@@ -345,7 +344,6 @@ export class ZonedDateTime {
     const { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const timeZone = GetSlot(this, TIME_ZONE);
     const calendar = GetSlot(this, CALENDAR);
     const epochNanoseconds = ES.AddZonedDateTime(
@@ -362,7 +360,7 @@ export class ZonedDateTime {
       milliseconds,
       microseconds,
       nanoseconds,
-      overflow
+      options
     );
     const Construct = ES.SpeciesConstructor(this, ZonedDateTime);
     const result = new Construct(epochNanoseconds, timeZone, calendar);
@@ -375,7 +373,6 @@ export class ZonedDateTime {
     const { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = duration;
     ES.RejectDurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
     const timeZone = GetSlot(this, TIME_ZONE);
     const calendar = GetSlot(this, CALENDAR);
     const epochNanoseconds = ES.AddZonedDateTime(
@@ -392,7 +389,7 @@ export class ZonedDateTime {
       -milliseconds,
       -microseconds,
       -nanoseconds,
-      overflow
+      options
     );
     const Construct = ES.SpeciesConstructor(this, ZonedDateTime);
     const result = new Construct(epochNanoseconds, timeZone, calendar);
@@ -451,6 +448,7 @@ export class ZonedDateTime {
             'or smaller because day lengths can vary between time zones due to DST or time zone offset changes.'
         );
       }
+      const untilOptions = { ...options, largestUnit };
       ({
         years,
         months,
@@ -462,7 +460,7 @@ export class ZonedDateTime {
         milliseconds,
         microseconds,
         nanoseconds
-      } = ES.DifferenceZonedDateTime(ns1, ns2, timeZone, calendar, largestUnit));
+      } = ES.DifferenceZonedDateTime(ns1, ns2, timeZone, calendar, largestUnit, untilOptions));
       ({
         years,
         months,
@@ -575,6 +573,7 @@ export class ZonedDateTime {
             'or smaller because day lengths can vary between time zones due to DST or time zone offset changes.'
         );
       }
+      const untilOptions = { ...options, largestUnit };
       ({
         years,
         months,
@@ -586,7 +585,7 @@ export class ZonedDateTime {
         milliseconds,
         microseconds,
         nanoseconds
-      } = ES.DifferenceZonedDateTime(ns1, ns2, timeZone, calendar, largestUnit));
+      } = ES.DifferenceZonedDateTime(ns1, ns2, timeZone, calendar, largestUnit, untilOptions));
       ({
         years,
         months,
@@ -691,7 +690,7 @@ export class ZonedDateTime {
     const calendar = GetSlot(this, CALENDAR);
     const dtStart = new DateTime(GetSlot(dt, ISO_YEAR), GetSlot(dt, ISO_MONTH), GetSlot(dt, ISO_DAY), 0, 0, 0, 0, 0, 0);
     const instantStart = ES.GetTemporalInstantFor(timeZone, dtStart, 'compatible');
-    const endNs = ES.AddZonedDateTime(instantStart, timeZone, calendar, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 'constrain');
+    const endNs = ES.AddZonedDateTime(instantStart, timeZone, calendar, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0);
     const dayLengthNs = endNs.subtract(GetSlot(instantStart, EPOCHNANOSECONDS));
     ({ year, month, day, hour, minute, second, millisecond, microsecond, nanosecond } = ES.RoundDateTime(
       year,
@@ -836,13 +835,13 @@ export class ZonedDateTime {
   }
   static from(item, options = undefined) {
     options = ES.NormalizeOptionsObject(options);
-    const overflow = ES.ToTemporalOverflow(options);
-    const disambiguation = ES.ToTemporalDisambiguation(options);
-    const offset = ES.ToTemporalOffset(options, 'reject');
     if (ES.IsTemporalZonedDateTime(item)) {
+      ES.ToTemporalOverflow(options); // validate and ignore
+      ES.ToTemporalDisambiguation(options);
+      ES.ToTemporalOffset(options, 'reject');
       return new ZonedDateTime(GetSlot(item, EPOCHNANOSECONDS), GetSlot(item, TIME_ZONE), GetSlot(item, CALENDAR));
     }
-    return ES.ToTemporalZonedDateTime(item, this, overflow, disambiguation, offset);
+    return ES.ToTemporalZonedDateTime(item, this, options);
   }
   static compare(one, two) {
     one = ES.ToTemporalZonedDateTime(one, ZonedDateTime);
diff --git a/spec/abstractops.html b/spec/abstractops.html
index b89c385c2d..9d8909d191 100644
--- a/spec/abstractops.html
+++ b/spec/abstractops.html
@@ -571,19 +571,9 @@ <h1>ToRelativeTemporalObject ( _options_ )</h1>
         1. Let _calendar_ be ? GetOptionalTemporalCalendar(_value_).
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"*, *"year"* »).
         1. Let _fields_ be ? ToTemporalDateTimeFields(_value_, _fieldNames_).
-        1. Let _temporalDate_ be ? DateFromFields(_calendar_, _fields_, %Temporal.PlainDate%).
-        1. Let _timeResult_ be ? ToTemporalTimeRecord(_fields_).
-        1. Let _result_ be the new Record {
-            [[Year]]: _temporalDate_.[[ISOYear]],
-            [[Month]]: _temporalDate_.[[ISOMonth]],
-            [[Day]]: _temporalDate_.[[ISODay]],
-            [[Hour]]: _timeResult_.[[Hour]],
-            [[Minute]]: _timeResult_.[[Minute]],
-            [[Second]]: _timeResult_.[[Second]],
-            [[Millisecond]]: _timeResult_.[[Millisecond]],
-            [[Microsecond]]: _timeResult_.[[Microsecond]],
-            [[Nanosecond]]: _timeResult_.[[Nanosecond]]
-          }.
+        1. Let _options_ be ! OrdinaryObjectCreate(%Object.prototype%).
+        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, *"constrain"*).
+        1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Let _offset_ be ? Get(_value_, *"offset"*).
         1. Let _timeZone_ be ? Get(_value_, *"timeZone"*).
       1. Else,
@@ -648,6 +638,22 @@ <h1>LargerOfTwoTemporalDurationUnits ( _u1_, _u2_ )</h1>
     </emu-alg>
   </emu-clause>
 
+  <emu-clause id="sec-temporal-mergelargestunitoption" aoid="MergeLargestUnitOption">
+    <h1>MergeLargestUnitOption ( _options_, _largestUnit_ )</h1>
+    <p>
+      The abstract operation MergeLargestUnitOption returns a new plain Object with the properties copied from the _options_ Object, and the `largestUnit` property set to _largestUnit_.
+    </p>
+    <emu-alg>
+      1. Let _merged_ be ! OrdinaryObjectCreate(%Object.prototype%).
+      1. Let _keys_ be ? EnumerableOwnPropertyNames(_options_, ~key~).
+      1. For each element _nextKey_ of _keys_, do
+        1. Let _propValue_ be ? Get(_options_, _nextKey_).
+        1. Perform ? Set(_merged_, _nextKey_, _propValue_, *true*).
+      1. Perform ? Set(_merged_, *"largestUnit"*, _largestUnit_, *true*).
+      1. Return _merged_.
+    </emu-alg>
+  </emu-clause>
+
   <emu-clause id="sec-temporal-maximumtemporaldurationroundingincrement" aoid="MaximumTemporalDurationRoundingIncrement">
     <h1>MaximumTemporalDurationRoundingIncrement ( _unit_ )</h1>
     <emu-alg>
diff --git a/spec/calendar.html b/spec/calendar.html
index 615555c830..0dd01b8945 100644
--- a/spec/calendar.html
+++ b/spec/calendar.html
@@ -63,15 +63,9 @@ <h1>CalendarMergeFields ( _calendar_, _fields_, _additionalFields_ )</h1>
     </emu-clause>
 
     <emu-clause id="sec-temporal-calendardateadd" aoid="CalendarDateAdd">
-      <h1>CalendarDateAdd ( _calendar_, _date_, _duration_, _constructor_ [ , _overflow_ ] )</h1>
+      <h1>CalendarDateAdd ( _calendar_, _date_, _duration_, _constructor_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
-        1. If _overflow_ is *undefined*, then
-          1. Set _overflow_ to *"constrain"*.
-        1. Else,
-          1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
-        1. Let _options_ be ! ObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _dateAdd_ be ? Get(_calendar_, *"dateAdd"*).
         1. Let _addedDate_ be ? Call(_dateAdd_, _calendar_, « _date_, _duration_, _options_, _constructor_ »).
         1. Perform ? RequireInternalSlot(_addedDate_, [[InitializedTemporalDate]]).
@@ -80,11 +74,9 @@ <h1>CalendarDateAdd ( _calendar_, _date_, _duration_, _constructor_ [ , _overflo
     </emu-clause>
 
     <emu-clause id="sec-temporal-calendardateuntil" aoid="CalendarDateUntil">
-      <h1>CalendarDateUntil ( _calendar_, _one_, _two_, _largestUnit_ )</h1>
+      <h1>CalendarDateUntil ( _calendar_, _one_, _two_, _options_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
-        1. Let _options_ be ! ObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"largestUnit"*, _largestUnit_).
         1. Let _dateUntil_ be ? Get(_calendar_, *"dateUntil"*).
         1. Let _duration_ be ? Call(_dateUntil_ , _calendar_, « _one_, _two_, _options_ »).
         1. Perform ? RequireInternalSlot(_duration_, [[InitializedTemporalDuration]]).
@@ -140,16 +132,10 @@ <h1>CalendarFrom ( _identifier_ )</h1>
     </emu-clause>
 
     <emu-clause id="sec-temporal-datefromfields" aoid="DateFromFields">
-      <h1>DateFromFields ( _calendar_, _fields_, _constructor_ [ , _overflow_ ] )</h1>
+      <h1>DateFromFields ( _calendar_, _fields_, _constructor_, _options_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
         1. Assert: Type(_fields_) is Object.
-        1. If _overflow_ is *undefined*, then
-          1. Set _overflow_ to *"constrain"*.
-        1. Else,
-          1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
-        1. Let _options_ be ! ObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _dateFromFields_ be ? Get(_calendar_, *"dateFromFields"*).
         1. Let _date_ be ? Call(_dateFromFields_, _calendar_, « _fields_, _options_, _constructor_ »).
         1. Perform ? RequireInternalSlot(_date_, [[InitializedTemporalDate]]).
@@ -158,16 +144,10 @@ <h1>DateFromFields ( _calendar_, _fields_, _constructor_ [ , _overflow_ ] )</h1>
     </emu-clause>
 
     <emu-clause id="sec-temporal-yearmonthfromfields" aoid="YearMonthFromFields">
-      <h1>YearMonthFromFields ( _calendar_, _fields_, _constructor_ [ , _overflow_ ] )</h1>
+      <h1>YearMonthFromFields ( _calendar_, _fields_, _constructor_, _options_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
         1. Assert: Type(_fields_) is Object.
-        1. If _overflow_ is *undefined*, then
-          1. Set _overflow_ to *"constrain"*.
-        1. Else,
-          1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
-        1. Let _options_ be ! ObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _yearMonthFromFields_ be ? Get(_calendar_, *"yearMonthFromFields"*).
         1. Let _yearMonth_ be ? Call(_yearMonthFromFields_, _calendar_, « _fields_, _options_, _constructor_ »).
         1. Perform ? RequireInternalSlot(_yearMonth_, [[InitializedTemporalYearMonth]]).
@@ -176,16 +156,10 @@ <h1>YearMonthFromFields ( _calendar_, _fields_, _constructor_ [ , _overflow_ ] )
     </emu-clause>
 
     <emu-clause id="sec-temporal-monthdayfromfields" aoid="MonthDayFromFields">
-      <h1>MonthDayFromFields ( _calendar_, _fields_, _constructor_ [ , _overflow_ ] )</h1>
+      <h1>MonthDayFromFields ( _calendar_, _fields_, _constructor_, _options_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
         1. Assert: Type(_fields_) is Object.
-        1. If _overflow_ is *undefined*, then
-          1. Set _overflow_ to *"constrain"*.
-        1. Else,
-          1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
-        1. Let _options_ be ! ObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _monthDayFromFields_ be ? Get(_calendar_, *"monthDayFromFields"*).
         1. Let _monthDay_ be ? Call(_monthDayFromFields_, _calendar_, « _fields_, _options_, _constructor_ »).
         1. Perform ? RequireInternalSlot(_monthDay_, [[InitializedTemporalMonthDay]]).
diff --git a/spec/duration.html b/spec/duration.html
index 9e570f97d2..8ae95eb2da 100644
--- a/spec/duration.html
+++ b/spec/duration.html
@@ -858,7 +858,7 @@ <h1>CalculateOffsetShift ( _relativeTo_, _y_, _mon_, _d_, _h_, _min_, _s_, _ms_,
         1. If Type(_relativeTo_) is not Object or _relativeTo_ does not have an [[InitializedTemporalZonedDateTime]] internal slot, return 0.
         1. Let _instant_ be ? CreateTemporalInstant(_relativeTo_.[[Nanoseconds]]).
         1. Let _offsetBefore_ be ? GetOffsetNanosecondsFor(_relativeTo_.[[TimeZone]], _instant_).
-        1. Let _after_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], _y_, _mon_, _d_, _h_, _min_, _s_, _ms_, _mus_, _ns_, *"constrain"*).
+        1. Let _after_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], _y_, _mon_, _d_, _h_, _min_, _s_, _ms_, _mus_, _ns_).
         1. Let _instantAfter_ be ? CreateTemporalInstant(_after_).
         1. Let _offsetAfter_ be ? GetOffsetNanosecondsFor(_relativeTo_.[[TimeZone]], _instantAfter_).
         1. Return _offsetAfter_ − _offsetBefore_.
@@ -887,7 +887,7 @@ <h1>TotalDurationNanoseconds ( _days_, _hours_, _minutes_, _seconds_, _milliseco
       <h1>BalanceDuration ( _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, _largestUnit_ [ , _relativeTo_ ] )</h1>
       <emu-alg>
         1. If _relativeTo_ has an [[InitializedTemporalZonedDateTime]] internal slot, then
-          1. Let _endNs_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, *"constrain"*).
+          1. Let _endNs_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_).
           1. Set _nanoseconds_ to _endNs_ − _relativeTo_.[[Nanoseconds]].
         1. Else,
           1. Set _nanoseconds_ to ! TotalDurationNanoseconds(_days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, 0).
@@ -1168,8 +1168,8 @@ <h1>AddDuration ( _y1_, _mon1_, _w1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _
           1. Assert: _relativeTo_ has an [[InitializedTemporalZonedDateTime]] internal slot.
           1. Let _timeZone_ be _relativeTo_.[[TimeZone]].
           1. Let _calendar_ be _relativeTo_.[[Calendar]].
-          1. Let _intermediateNs_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _timeZone_, _calendar_, _y1_, _mon1_, _w1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, *"constrain"*).
-          1. Let _endNs_ be ? AddZonedDateTime(_intermediateNs_, _timeZone_, _calendar_, _y1_, _mon1_, _w1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, *"constrain"*).
+          1. Let _intermediateNs_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _timeZone_, _calendar_, _y1_, _mon1_, _w1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_).
+          1. Let _endNs_ be ? AddZonedDateTime(_intermediateNs_, _timeZone_, _calendar_, _y2_, _mon2_, _w2_, _d2_, _h2_, _min2_, _s2_, _ms2_, _mus2_, _ns2_).
           1. If _largestUnit_ is not one of *"years"*, *"months"*, *"weeks"*, or *"days"*, then
             1. Let _diffNs_ be ! DifferenceInstant(_relativeTo_.[[Nanoseconds]], _endNs_, 1, *"nanoseconds"*, *"nearest"*).
             1. Let _result_ be ! BalanceDuration(0, 0, 0, 0, 0, 0, _diffNs_, _largestUnit_).
@@ -1250,7 +1250,7 @@ <h1>MoveRelativeZonedDateTime ( _zonedDateTime_, _years_, _months_, _weeks_, _da
         The abstract operation MoveRelativeZonedDateTime adjusts the calendar part of a Temporal.ZonedDateTime instance for use as the "relative-to" parameter of another operation.
       </p>
       <emu-alg>
-        1. Let _intermediateNs_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _zonedDateTime_.[[TimeZone]], _zonedDateTime_.[[Calendar]], _years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0, *"constrain"*).
+        1. Let _intermediateNs_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _zonedDateTime_.[[TimeZone]], _zonedDateTime_.[[Calendar]], _years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0).
         1. Let _intermediate_ be ? CreateTemporalZonedDateTime(_intermediateNs_, _zonedDateTime_.[[TimeZone]], _zonedDateTime_.[[Calendar]]).
       </emu-alg>
     </emu-clause>
@@ -1420,8 +1420,8 @@ <h1>AdjustRoundedDurationDays ( _years_, _months_, _weeks_, _days_, _hours_, _mi
             }.
         1. Let _timeRemainderNs_ be ? TotalDurationNanoseconds(0, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, 0).
         1. Let _direction_ be ! Sign(_timeRemainderNs_).
-        1. Let _dayStart_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], _years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0, *"constrain"*).
-        1. Let _dayEnd_ be ? AddZonedDateTime(_dayStart_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _direction_, 0, 0, 0, 0, 0, 0, *"constrain"*).
+        1. Let _dayStart_ be ? AddZonedDateTime(_relativeTo_.[[Nanoseconds]], _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], _years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0).
+        1. Let _dayEnd_ be ? AddZonedDateTime(_dayStart_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _direction_, 0, 0, 0, 0, 0, 0).
         1. Let _dayLengthNs_ be _dayEnd_ − _dayStart_.
         1. If (_timeRemainderNs_ − _dayLengthNs_) × _direction_ &lt; 0, then
           1. Return the new Record {
diff --git a/spec/plaindate.html b/spec/plaindate.html
index b5b5e80be8..d2e39275ed 100644
--- a/spec/plaindate.html
+++ b/spec/plaindate.html
@@ -68,10 +68,10 @@ <h1>Temporal.PlainDate.from ( _item_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Let _constructor_ be the *this* value.
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. If Type(_item_) is Object and _item_ has an [[InitializedTemporalDate]] internal slot, then
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Return ? CreateTemporalDateFromStatic(_constructor_, _item_.[[ISOYear]], _item_.[[ISOMonth]], _item_.[[ISODay]], _item_.[[Calendar]]).
-        1. Return ? ToTemporalDate(_item_, _constructor_, _overflow_).
+        1. Return ? ToTemporalDate(_item_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -354,12 +354,9 @@ <h1>Temporal.PlainDate.prototype.add ( _temporalDurationLike_ [ , _options_ ] )<
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Let _balanceResult_ be ? BalanceDuration(_duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], *"days"*).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
-        1. Let _dateAddOptions_ be ! OrdinaryObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_dateAddOptions_, *"overflow"*, _overflow_).
         1. Let _constructor_ be ? SpeciesConstructor(_temporalDate_, %Temporal.PlainDate%).
         1. Let _dateAdd_ be ? Get(_calendar_, *"dateAdd"*).
-        1. Return ? Call(_dateAdd_, _calendar_, « _temporalDate_, _duration_, _dateAddOptions_, _constructor_ »).
+        1. Return ? Call(_dateAdd_, _calendar_, « _temporalDate_, _duration_, _options_, _constructor_ »).
       </emu-alg>
     </emu-clause>
 
@@ -376,13 +373,10 @@ <h1>Temporal.PlainDate.prototype.subtract ( _temporalDurationLike_ [ , _options_
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Let _balanceResult_ be ? BalanceDuration(_duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], *"days"*).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _negatedDuration_ be ? CreateTemporalDuration(−_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_duration_.[[Days]], −_duration_.[[Hours]], −_duration_.[[Minutes]], −_duration_.[[Seconds]], −_duration_.[[Milliseconds]], −_duration_.[[Microseconds]], −_duration_.[[Nanoseconds]]).
-        1. Let _dateAddOptions_ be ! OrdinaryObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_dateAddOptions_, *"overflow"*, _overflow_).
         1. Let _constructor_ be ? SpeciesConstructor(_temporalDate_, %Temporal.PlainDate%).
         1. Let _dateAdd_ be ? Get(_calendar_, *"dateAdd"*).
-        1. Return ? Call(_dateAdd_, _calendar_, « _temporalDate_, _negatedDuration_, _dateAddOptions_, _constructor_ »).
+        1. Return ? Call(_dateAdd_, _calendar_, « _temporalDate_, _negatedDuration_, _options_, _constructor_ »).
       </emu-alg>
     </emu-clause>
 
@@ -407,11 +401,10 @@ <h1>Temporal.PlainDate.prototype.with ( _temporalDateLike_ [ , _options_ ] )</h1
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"*, *"year"* »).
         1. Let _partialDate_ be ? ToPartialDate(_temporalDateLike_, _fieldNames_).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _fields_ be ? ToTemporalDateFields(_temporalDate_, _fieldNames_).
         1. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialDate_).
         1. Let _constructor_ be ? SpeciesConstructor(_temporalDate_, %Temporal.PlainDate%).
-        1. Return ? DateFromFields(_calendar_, _fields_, _constructor_, _overflow_).
+        1. Return ? DateFromFields(_calendar_, _fields_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -447,7 +440,7 @@ <h1>Temporal.PlainDate.prototype.until ( _other_ [ , _options_ ] )</h1>
         1. Perform ? ValidateTemporalUnitRange(_largestUnit_, _smallestUnit_).
         1. Let _roundingMode_ be ? ToTemporalRoundingMode(_options_, *"trunc"*).
         1. Let _roundingIncrement_ be ? ToTemporalRoundingIncrement(_options_, *undefined*, *false*).
-        1. Let _result_ be ? CalendarDateUntil(_temporalDate_.[[Calendar]], _temporalDate_, _other_, _largestUnit_).
+        1. Let _result_ be ? CalendarDateUntil(_temporalDate_.[[Calendar]], _temporalDate_, _other_, _options_).
         1. If _smallestUnit_ is not *"days"* or _roundingIncrement_ ≠ 1, then
           1. Let _relativeTo_ be ! CreateTemporalDateTime(_temporalDate_.[[ISOYear]], _temporalDate_.[[ISOMonth]], _temporalDate_.[[ISODay]], 0, 0, 0, 0, 0, 0, _temporalDate_.[[Calendar]]).
           1. Set _result_ to ? RoundDuration(_result_.[[Years]], _result_.[[Months]], _result_.[[Weeks]], _result_.[[Days]], 0, 0, 0, 0, 0, 0, _roundingIncrement_, _smallestUnit_, _roundingMode_, _relativeTo_).
@@ -474,7 +467,7 @@ <h1>Temporal.PlainDate.prototype.since ( _other_ [ , _options_ ] )</h1>
         1. Let _roundingMode_ be ? ToTemporalRoundingMode(_options_, *"trunc"*).
         1. Set _roundingMode_ to ! NegateTemporalRoundingMode(_roundingMode_).
         1. Let _roundingIncrement_ be ? ToTemporalRoundingIncrement(_options_, *undefined*, *false*).
-        1. Let _result_ be ? CalendarDateUntil(_temporalDate_.[[Calendar]], _other_, _temporalDate_, _largestUnit_).
+        1. Let _result_ be ? CalendarDateUntil(_temporalDate_.[[Calendar]], _other_, _temporalDate_, _options_).
         1. If _smallestUnit_ is *"days"* and _roundingIncrement_ = 1, then
           1. Return ? CreateTemporalDuration(_result_.[[Years]], _result_.[[Months]], _result_.[[Weeks]], _result_.[[Days]], 0, 0, 0, 0, 0, 0).
         1. Let _relativeTo_ be ! CreateTemporalDateTime(_temporalDate_.[[ISOYear]], _temporalDate_.[[ISOMonth]], _temporalDate_.[[ISODay]], 0, 0, 0, 0, 0, 0, _temporalDate_.[[Calendar]]).
@@ -715,21 +708,21 @@ <h1>CreateTemporalDateFromStatic ( _constructor_, _isoYear_, _isoMonth_, _isoDay
     </emu-clause>
 
     <emu-clause id="sec-temporal-totemporaldate" aoid="ToTemporalDate">
-      <h1>ToTemporalDate ( _item_ [ , _constructor_ [ , _overflow_ ] ] )</h1>
+      <h1>ToTemporalDate ( _item_ [ , _constructor_ [ , _options_ ] ] )</h1>
       <p>
         The abstract operation ToTemporalDate returns its argument _item_ if it is already a Temporal.PlainDate instance, converts _item_ to a new Temporal.PlainDate instance if possible, and throws otherwise.
       </p>
       <emu-alg>
         1. If _constructor_ is not given, set it to %Temporal.PlainDate%.
-        1. If _overflow_ is not given, set it to *"constrain"*.
-        1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
+        1. If _options_ is not present, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. If Type(_item_) is Object, then
           1. If _item_ has an [[InitializedTemporalDate]] internal slot, then
             1. Return _item_.
           1. Let _calendar_ be ? GetOptionalTemporalCalendar(_item_).
           1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"*, *"year"* »).
           1. Let _fields_ be ? ToTemporalDateFields(_item_, _fieldNames_).
-          1. Return ? DateFromFields(_calendar_, _fields_, _constructor_, _overflow_).
+          1. Return ? DateFromFields(_calendar_, _fields_, _constructor_, _options_).
+        1. Perform ? ToTemporalOverflow(_options_).
         1. Let _string_ be ? ToString(_item_).
         1. Let _result_ be ? ParseTemporalDateString(_string_).
         1. If ! ValidateDate(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]) is *false*, then
diff --git a/spec/plaindatetime.html b/spec/plaindatetime.html
index 8ad8cdd783..85d76f9c5c 100644
--- a/spec/plaindatetime.html
+++ b/spec/plaindatetime.html
@@ -74,10 +74,10 @@ <h1>Temporal.PlainDateTime.from ( _item_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Let _constructor_ be the *this* value.
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. If Type(_item_) is Object and _item_ has an [[InitializedTemporalDateTime]] internal slot, then
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Return ? CreateTemporalDateTimeFromStatic(_constructor_, _item_.[[ISOYear]], _item_.[[ISOMonth]], _item_.[[ISODay]], _item_.[[ISOHour]], _item_.[[ISOMinute]], _item_.[[ISOSecond]], _item_.[[ISOMillisecond]], _item_.[[ISOMicrosecond]], _item_.[[ISONanosecond]], _item_.[[Calendar]]).
-        1. Return ? ToTemporalDateTime(_item_, _constructor_, _overflow_).
+        1. Return ? ToTemporalDateTime(_item_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -401,10 +401,9 @@ <h1>Temporal.PlainDateTime.prototype.with ( _temporalDateTimeLike_ [ , _options_
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"hour"*, *"microsecond"*, *"millisecond"*, *"minute"*, *"month"*, *"nanosecond"*, *"second"*, *"year"* »).
         1. Let _partialDateTime_ be ? ToPartialDateTime(_temporalDateTimeLike_, _fieldNames_).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _fields_ be ? ToTemporalDateTimeFields(_datetime_, _fieldNames_).
         1. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialDateTime_).
-        1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _overflow_).
+        1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Assert: ! ValidateDateTime(_year_, _month_, _day_, _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *true*.
         1. Return ? CreateTemporalDateTimeFromInstance(_dateTime_, _result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]], _calendar_).
       </emu-alg>
@@ -467,8 +466,7 @@ <h1>Temporal.PlainDateTime.prototype.add ( _temporalDurationLike_ [ , _options_
         1. Let _duration_ be ? ToLimitedTemporalDuration(_temporalDurationLike_, « »).
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
-        1. Let _result_ be ? AddDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], _duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], _overflow_).
+        1. Let _result_ be ? AddDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], _duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], _options_).
         1. Assert: ! ValidateDateTime(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *true*.
         1. Return ? CreateTemporalDateTimeFromInstance(_dateTime_, _result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]], _dateTime_.[[Calendar]]).
       </emu-alg>
@@ -486,8 +484,7 @@ <h1>Temporal.PlainDateTime.prototype.subtract ( _temporalDurationLike_ [ , _opti
         1. Let _duration_ be ? ToLimitedTemporalDuration(_temporalDurationLike_, « »).
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
-        1. Let _result_ be ? AddDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], −_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_duration_.[[Days]], −_duration_.[[Hours]], −_duration_.[[Minutes]], −_duration_.[[Seconds]], −_duration_.[[Milliseconds]], −_duration_.[[Microseconds]], −_duration_.[[Nanoseconds]], _overflow_).
+        1. Let _result_ be ? AddDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], −_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_duration_.[[Days]], −_duration_.[[Hours]], −_duration_.[[Minutes]], −_duration_.[[Seconds]], −_duration_.[[Milliseconds]], −_duration_.[[Microseconds]], −_duration_.[[Nanoseconds]], _options_).
         1. Assert: ! ValidateDateTime(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *true*.
         1. Return ? CreateTemporalDateTimeFromInstance(_dateTime_, _result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]], _dateTime_.[[Calendar]]).
       </emu-alg>
@@ -512,7 +509,7 @@ <h1>Temporal.PlainDateTime.prototype.until ( _other_ [ , _options_ ] )</h1>
         1. Let _roundingMode_ be ? ToTemporalRoundingMode(_options_, *"trunc"*).
         1. Let _maximum_ be ! MaximumTemporalDurationRoundingIncrement(_smallestUnit_).
         1. Let _roundingIncrement_ be ? ToTemporalRoundingIncrement(_options_, _maximum_, *false*).
-        1. Let _diff_ be ? DifferenceDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _other_.[[ISOYear]], _other_.[[ISOMonth]], _other_.[[ISODay]], _other_.[[ISOHour]], _other_.[[ISOMinute]], _other_.[[ISOSecond]], _other_.[[ISOMillisecond]], _other_.[[ISOMicrosecond]], _other_.[[ISONanosecond]], _dateTime_.[[Calendar]], _largestUnit_).
+        1. Let _diff_ be ? DifferenceDateTime(_dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _other_.[[ISOYear]], _other_.[[ISOMonth]], _other_.[[ISODay]], _other_.[[ISOHour]], _other_.[[ISOMinute]], _other_.[[ISOSecond]], _other_.[[ISOMillisecond]], _other_.[[ISOMicrosecond]], _other_.[[ISONanosecond]], _dateTime_.[[Calendar]], _largestUnit_, _options_).
         1. Let _roundResult_ be ? RoundDuration(_diff_.[[Years]], _diff_.[[Months]], _diff_.[[Weeks]], _diff_.[[Days]], _diff_.[[Hours]], _diff_.[[Minutes]], _diff_.[[Seconds]], _diff_.[[Milliseconds]], _diff_.[[Microseconds]], _diff_.[[Nanoseconds]], _roundingIncrement_, _smallestUnit_, _roundingMode_, _dateTime_).
         1. Let _result_ be ! BalanceDuration(_roundResult_.[[Days]], _roundResult_.[[Hours]], _roundResult_.[[Minutes]], _roundResult_.[[Seconds]], _roundResult_.[[Milliseconds]], _roundResult_.[[Microseconds]], _roundResult_.[[Nanoseconds]], _largestUnit_).
         1. Return ? CreateTemporalDuration(_roundResult_.[[Years]], _roundResult_.[[Months]], _roundResult_.[[Weeks]], _result_.[[Days]], _result_.[[Hours]], _result_.[[Minutes]], _result_.[[Seconds]], _result_.[[Milliseconds]], _result_.[[Microseconds]], _result_.[[Nanoseconds]]).
@@ -539,7 +536,7 @@ <h1>Temporal.PlainDateTime.prototype.since ( _other_ [ , _options_ ] )</h1>
         1. Set _roundingMode_ to ! NegateTemporalRoundingMode(_roundingMode_).
         1. Let _maximum_ be ! MaximumTemporalDurationRoundingIncrement(_smallestUnit_).
         1. Let _roundingIncrement_ be ? ToTemporalRoundingIncrement(_options_, _maximum_, *false*).
-        1. Let _diff_ be ? DifferenceDateTime(_other_.[[ISOYear]], _other_.[[ISOMonth]], _other_.[[ISODay]], _other_.[[ISOHour]], _other_.[[ISOMinute]], _other_.[[ISOSecond]], _other_.[[ISOMillisecond]], _other_.[[ISOMicrosecond]], _other_.[[ISONanosecond]], _dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], _largestUnit_).
+        1. Let _diff_ be ? DifferenceDateTime(_other_.[[ISOYear]], _other_.[[ISOMonth]], _other_.[[ISODay]], _other_.[[ISOHour]], _other_.[[ISOMinute]], _other_.[[ISOSecond]], _other_.[[ISOMillisecond]], _other_.[[ISOMicrosecond]], _other_.[[ISONanosecond]], _dateTime_.[[ISOYear]], _dateTime_.[[ISOMonth]], _dateTime_.[[ISODay]], _dateTime_.[[ISOHour]], _dateTime_.[[ISOMinute]], _dateTime_.[[ISOSecond]], _dateTime_.[[ISOMillisecond]], _dateTime_.[[ISOMicrosecond]], _dateTime_.[[ISONanosecond]], _dateTime_.[[Calendar]], _largestUnit_, _options_).
         1. Let _roundResult_ be ? RoundDuration(−_diff_.[[Years]], −_diff_.[[Months]], −_diff_.[[Weeks]], −_diff_.[[Days]], −_diff_.[[Hours]], −_diff_.[[Minutes]], −_diff_.[[Seconds]], −_diff_.[[Milliseconds]], −_diff_.[[Microseconds]], −_diff_.[[Nanoseconds]], _roundingIncrement_, _smallestUnit_, _roundingMode_, _dateTime_).
         1. Let _result_ be ! BalanceDuration(−_roundResult_.[[Days]], −_roundResult_.[[Hours]], −_roundResult_.[[Minutes]], −_roundResult_.[[Seconds]], −_roundResult_.[[Milliseconds]], −_roundResult_.[[Microseconds]], −_roundResult_.[[Nanoseconds]], _largestUnit_).
         1. Return ? CreateTemporalDuration(−_roundResult_.[[Years]], −_roundResult_.[[Months]], −_roundResult_.[[Weeks]], _result_.[[Days]], _result_.[[Hours]], _result_.[[Minutes]], _result_.[[Seconds]], _result_.[[Milliseconds]], _result_.[[Microseconds]], _result_.[[Nanoseconds]]).
@@ -887,13 +884,14 @@ <h1>DateTimeWithinLimits ( _year_, _month_, _day_, _hour_, _minute_, _second_, _
     </emu-clause>
 
     <emu-clause id="sec-temporal-interprettemporaldatetimefields" aoid="InterpretTemporalDateTimeFields">
-      <h1>InterpretTemporalDateTimeFields ( _calendar_, _fields_, _overflow_ )</h1>
+      <h1>InterpretTemporalDateTimeFields ( _calendar_, _fields_, _options_ )</h1>
       <p>
         The abstract operation InterpretTemporalDateTimeFields interprets the date/time fields in the object _fields_ using the given _calendar_, and returns a Record with the fields according to the ISO calendar.
       </p>
       <emu-alg>
-        1. Let _temporalDate_ be ? DateFromFields(_calendar_, _fields_, %Temporal.PlainDate%, _overflow_).
+        1. Let _temporalDate_ be ? DateFromFields(_calendar_, _fields_, %Temporal.PlainDate%, _options_).
         1. Let _timeResult_ be ? ToTemporalTimeRecord(_fields_).
+        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _timeResult_ be ? RegulateTime(_timeResult_.[[Hour]], _timeResult_.[[Minute]], _timeResult_.[[Second]], _timeResult_.[[Millisecond]], _timeResult_.[[Microsecond]], _timeResult_.[[Nanosecond]], _overflow_).
         1. Return the new Record {
           [[Year]]: _temporalDate_.[[ISOYear]],
@@ -910,22 +908,22 @@ <h1>InterpretTemporalDateTimeFields ( _calendar_, _fields_, _overflow_ )</h1>
     </emu-clause>
 
     <emu-clause id="sec-temporal-totemporaldatetime" aoid="ToTemporalDateTime">
-      <h1>ToTemporalDateTime ( _item_ [ , _constructor_ [ , _overflow_ ] ] )</h1>
+      <h1>ToTemporalDateTime ( _item_ [ , _constructor_ [ , _options_ ] ] )</h1>
       <p>
         The abstract operation ToTemporalDateTime returns its argument _item_ if it is already a Temporal.PlainDateTime instance, converts _item_ to a new Temporal.PlainDateTime instance if possible, and throws otherwise.
       </p>
       <emu-alg>
         1. If _constructor_ is not given, set it to %Temporal.PlainDateTime%.
-        1. If _overflow_ is not given, set it to *"constrain"*.
-        1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
+        1. If _options_ is not given, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. If Type(_item_) is Object, then
           1. If _item_ has an [[InitializedTemporalDateTime]] internal slot, then
             1. Return _item_.
           1. Let _calendar_ be ? GetOptionalTemporalCalendar(_item_).
           1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"hour"*, *"microsecond"*, *"millisecond"*, *"minute"*, *"month"*, *"nanosecond"*, *"second"*, *"year"* »).
           1. Let _fields_ be ? ToTemporalDateTimeFields(_item_, _fieldNames_).
-          1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _overflow_).
+          1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Else,
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Let _string_ be ? ToString(_item_).
           1. Let _result_ be ? ParseTemporalDateTimeString(_string_).
           1. If ! ValidateDateTime(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *false*, then
@@ -1151,13 +1149,11 @@ <h1>CompareTemporalDateTime ( _y1_, _mon1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mu
     </emu-clause>
 
     <emu-clause id="sec-temporal-adddatetime" aoid="AddDateTime">
-      <h1>AddDateTime ( _year_, _month_, _day_, _hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_, _calendar_, _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, _overflow_ )</h1>
+      <h1>AddDateTime ( _year_, _month_, _day_, _hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_, _calendar_, _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, _options_ )</h1>
       <p>
         The abstract operation AddDateTime adds a duration to a combined date and time, according to the reckoning of the given _calendar_.
       </p>
       <emu-alg>
-        1. Let _options_ be ! OrdinaryObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _timeResult_ be ? AddTime(_hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_).
         1. Let _datePart_ be ? CreateTemporalDate(_year_, _month_, _day_, _calendar_).
         1. Let _dateDuration_ be ? CreateTemporalDuration(_years_, _months_, _weeks_, _days_ + _timeResult_.[[Days]]).
@@ -1200,22 +1196,22 @@ <h1>RoundDateTime ( _year_, _month_, _day_, _hour_, _minute_, _second_, _millise
     </emu-clause>
 
     <emu-clause id="sec-temporal-differencedatetime" aoid="DifferenceDateTime">
-      <h1>DifferenceDateTime ( _y1_, _mon1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, _y2_, _mon2_, _d2_, _h2_, _min2_, _s2_, _ms2_, _mus2_, _ns2_, _calendar_, _largestUnit_ )</h1>
+      <h1>DifferenceDateTime ( _y1_, _mon1_, _d1_, _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, _y2_, _mon2_, _d2_, _h2_, _min2_, _s2_, _ms2_, _mus2_, _ns2_, _calendar_, _largestUnit_ [ , _options_ ] )</h1>
       <p>
         The abstract operation DifferenceDateTime returns a Record with the elapsed duration from a first date and time, until a second date and time, according to the reckoning of the given _calendar_.
         The given date and time units are all in the ISO 8601 calendar.
-        The _largestUnit_ argument is used in _calendar_'s `dateUntil` method.
+        The _largestUnit_ and _options_ arguments are used in _calendar_'s `dateUntil` method.
       </p>
       <emu-alg>
+        1. If _options_ is not given, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. Let _timeDifference_ be ? DifferenceTime(_h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, _h2_, _min2_, _s2_, _ms2_, _mus2_, _ns2_).
         1. Let _balanceResult_ be ? BalanceDate(_y1_, _mon1_, _d1_ + _timeDifference_.[[Days]]).
         1. Let _date1_ be ? CreateTemporalDate(_balanceResult_.[[Year]], _balanceResult_.[[Month]], _balanceResult_.[[Day]]).
         1. Let _date2_ be ? CreateTemporalDate(_y2_, _mon2_, _d2_).
         1. Let _dateUntil_ be ? Get(_calendar_, *"dateUntil"*).
         1. Let _dateLargestUnit_ be ! LargerOfTwoTemporalUnits(*"days"*, _largestUnit_).
-        1. Let _options_ be ! OrdinaryObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"largestUnit"*, _dateLargestUnit_).
-        1. Let _dateDifference_ be ? Call(_dateUntil_, _calendar_, « _date1_, _date2_, _options_ »).
+        1. Let _untilOptions_ be ? MergeLargestUnitOption(_options_, _dateLargestUnit_).
+        1. Let _dateDifference_ be ? Call(_dateUntil_, _calendar_, « _date1_, _date2_, _untilOptions_ »).
         1. Return ? BalanceDuration(_dateDifference_.[[Years]], _dateDifference_.[[Months]], _dateDifference_.[[Weeks]], _dateDifference_.[[Days]], _timeDifference_.[[Hours]], _timeDifference_.[[Minutes]], _timeDifference_.[[Seconds]], _timeDifference_.[[Milliseconds]], _timeDifference_.[[Microseconds]], _timeDifference_.[[Nanoseconds]], _largestUnit_).
       </emu-alg>
     </emu-clause>
diff --git a/spec/plainmonthday.html b/spec/plainmonthday.html
index 78e78baaa2..267913a178 100644
--- a/spec/plainmonthday.html
+++ b/spec/plainmonthday.html
@@ -70,10 +70,10 @@ <h1>Temporal.PlainMonthDay.from ( _item_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Let _constructor_ be the *this* value.
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. If Type(_item_) is Object and _item_ has an [[InitializedTemporalMonthDay]] internal slot, then
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Return ? CreateTemporalMonthDayFromStatic(_constructor_, _item_.[[ISOMonth]], _item_.[[ISODay]], _item_.[[ISOYear]], _item_.[[Calendar]]).
-        1. Return ? ToTemporalMonthDay(_item_, _constructor_, _overflow_).
+        1. Return ? ToTemporalMonthDay(_item_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
   </emu-clause>
@@ -168,11 +168,10 @@ <h1>Temporal.PlainMonthDay.prototype.with ( _temporalMonthDayLike_ [ , _options_
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"* »).
         1. Let _partialMonthDay_ be ? ToPartialMonthDay(_temporalMonthDayLike_, _fieldNames_).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _fields_ be ? ToTemporalMonthDayFields(_monthDay_, _fieldNames_).
         1. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialMonthDay_).
         1. Let _constructor_ be ? SpeciesConstructor(_monthDay_, %Temporal.PlainMonthDay%).
-        1. Return ? MonthDayFromFields(_calendar_, _fields_, _constructor_, _overflow_).
+        1. Return ? MonthDayFromFields(_calendar_, _fields_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -356,21 +355,21 @@ <h1>Properties of Temporal.PlainMonthDay Instances</h1>
     <h1>Abstract operations</h1>
 
     <emu-clause id="sec-temporal-totemporalmonthday" aoid="ToTemporalMonthDay">
-      <h1>ToTemporalMonthDay ( _item_ [ , _constructor_ [ , _overflow_ ] ] )</h1>
+      <h1>ToTemporalMonthDay ( _item_ [ , _constructor_ [ , _options_ ] ] )</h1>
       <p>
         The abstract operation ToTemporalMonthDay returns its argument _item_ if it is already a Temporal.PlainMonthDay instance, converts _item_ to a new Temporal.PlainMonthDay instance if possible, and throws otherwise.
       </p>
       <emu-alg>
         1. If _constructor_ is not given, set it to %Temporal.PlainMonthDay%.
-        1. If _overflow_ is not given, set it to *"constrain"*.
-        1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
+        1. If _options_ is not given, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. If Type(_item_) is Object, then
           1. If _item_ has an [[InitializedTemporalMonthDay]] internal slot, then
             1. Return _item_.
           1. Let _calendar_ be ? GetOptionalTemporalCalendar(_item_).
           1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"month"* »).
           1. Let _fields_ be ? ToTemporalMonthDayFields(_item_, _fieldNames_).
-          1. Return ? MonthDayFromFields(_calendar_, _fields_, _overflow_, _constructor_).
+          1. Return ? MonthDayFromFields(_calendar_, _fields_, _constructor_, _options_).
+        1. Perform ? ToTemporalOverflow(_options_).
         1. Let _string_ be ? ToString(_item_).
         1. Let _result_ be ? ParseTemporalMonthDayString(_string_).
         1. If _result_.[[Year]] is *undefined*, then
diff --git a/spec/plainyearmonth.html b/spec/plainyearmonth.html
index 04c870ba91..347808a864 100644
--- a/spec/plainyearmonth.html
+++ b/spec/plainyearmonth.html
@@ -69,10 +69,10 @@ <h1>Temporal.PlainYearMonth.from ( _item_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Let _constructor_ be the *this* value.
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. If Type(_item_) is Object and _item_ has an [[InitializedTemporalYearMonth]] internal slot, then
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Return ? CreateTemporalYearMonthFromStatic(_constructor_, _item_.[[ISOYear]], _item_.[[ISOMonth]], _item_.[[Calendar]], _item_.[[ISODay]]).
-        1. Return ? ToTemporalYearMonth(_item_, _constructor_, _overflow_).
+        1. Return ? ToTemporalYearMonth(_item_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -241,11 +241,10 @@ <h1>Temporal.PlainYearMonth.prototype.with ( _temporalYearMonthLike_ [ , _option
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"month"*, *"year"* »).
         1. Let _partialYearMonth_ be ? ToPartialYearMonth(_temporalYearMonthLike_, _fieldNames_).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _fields_ be ? ToTemporalYearMonthFields(_yearMonth_, _fieldNames_).
         1. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialYearMonth_).
         1. Let _constructor_ be ? SpeciesConstructor(_yearMonth_, %Temporal.PlainYearMonth%).
-        1. Return ? YearMonthFromFields(_calendar_, _fields_, _constructor_, _overflow_).
+        1. Return ? YearMonthFromFields(_calendar_, _fields_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -262,7 +261,6 @@ <h1>Temporal.PlainYearMonth.prototype.add ( _temporalDurationLike_ [ , _options_
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Let _balanceResult_ be ? BalanceDuration(_duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], *"days"*).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _calendar_ be _yearMonth_.[[Calendar]].
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"month"*, *"year"* »).
         1. Let _sign_ be ! DurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _balanceResult_.[[Days]], 0, 0, 0, 0, 0, 0).
@@ -273,10 +271,10 @@ <h1>Temporal.PlainYearMonth.prototype.add ( _temporalDurationLike_ [ , _options_
           1. Let _day_ be 1.
         1. Let _date_ be ? CreateTemporalDate(_yearMonth_.[[ISOYear]], _yearMonth_.[[ISOMonth]], _day_, _calendar_).
         1. Let _durationToAdd_ be ? CreateTemporalDuration(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _balanceResult_.[[Days]], 0, 0, 0, 0, 0, 0).
-        1. Let _addedDate_ be ? CalendarDateAdd(_calendar_, _date_, _durationToAdd_, %Temporal.PlainDate%, _overflow_).
+        1. Let _addedDate_ be ? CalendarDateAdd(_calendar_, _date_, _durationToAdd_, %Temporal.PlainDate%, _options_).
         1. Let _addedDateFields_ be ToTemporalYearMonthFields(_addedDate_, _fieldNames_).
         1. Let _constructor_ be ? SpeciesConstructor(_yearMonth_, %Temporal.PlainYearMonth%).
-        1. Return ? YearMonthFromFields(_calendar_, _addedDateFields_, _constructor_, _overflow_).
+        1. Return ? YearMonthFromFields(_calendar_, _addedDateFields_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -293,7 +291,6 @@ <h1>Temporal.PlainYearMonth.prototype.subtract ( _temporalDurationLike_ [ , _opt
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Let _balanceResult_ be ? BalanceDuration(_duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], *"days"*).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _calendar_ be _yearMonth_.[[Calendar]].
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"month"*, *"year"* »).
         1. Let _sign_ be ! DurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _balanceResult_.[[Days]], 0, 0, 0, 0, 0, 0).
@@ -304,10 +301,10 @@ <h1>Temporal.PlainYearMonth.prototype.subtract ( _temporalDurationLike_ [ , _opt
           1. Let _day_ be 1.
         1. Let _date_ be ? CreateTemporalDate(_yearMonth_.[[ISOYear]], _yearMonth_.[[ISOMonth]], _day_, _calendar_).
         1. Let _durationToAdd_ be ? CreateTemporalDuration(−_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_balanceResult_.[[Days]], 0, 0, 0, 0, 0, 0).
-        1. Let _addedDate_ be ? CalendarDateAdd(_calendar_, _date_, _durationToAdd_, %Temporal.PlainDate%, _overflow_).
+        1. Let _addedDate_ be ? CalendarDateAdd(_calendar_, _date_, _durationToAdd_, %Temporal.PlainDate%, _options_).
         1. Let _addedDateFields_ be ToTemporalYearMonthFields(_addedDate_, _fieldNames_).
         1. Let _constructor_ be ? SpeciesConstructor(_yearMonth_, %Temporal.PlainYearMonth%).
-        1. Return ? YearMonthFromFields(_calendar_, _addedDateFields_, _constructor_, _overflow_).
+        1. Return ? YearMonthFromFields(_calendar_, _addedDateFields_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -337,7 +334,8 @@ <h1>Temporal.PlainYearMonth.prototype.until ( _other_ [ , _options_ ] )</h1>
         1. Let _thisFields_ be ToTemporalYearMonthFields(_yearMonth_, _fieldNames_).
         1. Perform ! CreateDataPropertyOrThrow(_thisFields_, *"day"*, *1*<sub>𝔽</sub>).
         1. Let _thisDate_ be ? DateFromFields(_calendar_, _thisFields_, %Temporal.PlainDate%).
-        1. Let _result_ be ? CalendarDateUntil(_calendar_, _thisDate_, _otherDate_, _largestUnit_).
+        1. Let _untilOptions_ be ? MergeLargestUnitOption(_options_, _largestUnit_).
+        1. Let _result_ be ? CalendarDateUntil(_calendar_, _thisDate_, _otherDate_, _untilOptions_).
         1. If _smallestUnit_ is *"months"* and _roundingIncrement_ = 1, then
           1. Return ? CreateTemporalDuration(_result_.[[Years]], _result_.[[Months]], 0, 0, 0, 0, 0, 0, 0).
         1. Let _relativeTo_ be ? CreateTemporalDateTime(_thisDate_.[[ISOYear]], _thisDate_.[[ISOMonth]], _thisDate_.[[ISODay]], 0, 0, 0, 0, 0, 0, _calendar_).
@@ -373,7 +371,8 @@ <h1>Temporal.PlainYearMonth.prototype.since ( _other_ [ , _options_ ] )</h1>
         1. Let _thisFields_ be ToTemporalYearMonthFields(_yearMonth_, _fieldNames_).
         1. Perform ! CreateDataPropertyOrThrow(_thisFields_, *"day"*, *1*<sub>𝔽</sub>).
         1. Let _thisDate_ be ? DateFromFields(_calendar_, _thisFields_, %Temporal.PlainDate%).
-        1. Let _result_ be ? CalendarDateUntil(_calendar_, _thisDate_, _otherDate_, _largestUnit_).
+        1. Let _untilOptions_ be ? MergeLargestUnitOption(_options_, _largestUnit_).
+        1. Let _result_ be ? CalendarDateUntil(_calendar_, _thisDate_, _otherDate_, _untilOptions_).
         1. If _smallestUnit_ is *"months"* and _roundingIncrement_ = 1, then
           1. Return ? CreateTemporalDuration(−_result_.[[Years]], −_result_.[[Months]], 0, 0, 0, 0, 0, 0, 0).
         1. Let _relativeTo_ be ? CreateTemporalDateTime(_thisDate_.[[ISOYear]], _thisDate_.[[ISOMonth]], _thisDate_.[[ISODay]], 0, 0, 0, 0, 0, 0, _calendar_).
@@ -474,7 +473,9 @@ <h1>Temporal.PlainYearMonth.prototype.toPlainDate ( _item_ )</h1>
             1. Throw a *TypeError* exception.
           1. Let _value_ be ? ToIntegerOrInfinity(_value_).
           1. Perform ! CreateDataPropertyOrThrow(_fields_, _property_, _value_).
-        1. Return ? DateFromFields(_calendar_, _fields_, *"reject"*, %Temporal.PlainDate%).
+        1. Let _options_ be ! OrdinaryObjectCreate(%Object.prototype%).
+        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, *"reject"*).
+        1. Return ? DateFromFields(_calendar_, _fields_, _options_, %Temporal.PlainDate%).
       </emu-alg>
     </emu-clause>
 
@@ -563,21 +564,21 @@ <h1>Properties of Temporal.PlainYearMonth Instances</h1>
     <h1>Abstract operations</h1>
 
     <emu-clause id="sec-temporal-totemporalyearmonth" aoid="ToTemporalYearMonth">
-      <h1>ToTemporalYearMonth ( _item_ [ , _constructor_ [ , _overflow_ ] ] )</h1>
+      <h1>ToTemporalYearMonth ( _item_ [ , _constructor_ [ , _options_ ] ] )</h1>
       <p>
         The abstract operation ToTemporalYearMonth returns its argument _item_ if it is already a Temporal.PlainYearMonth instance, converts _item_ to a new Temporal.PlainYearMonth instance if possible, and throws otherwise.
       </p>
       <emu-alg>
         1. If _constructor_ is not given, set it to %Temporal.PlainYearMonth%.
-        1. If _overflow_ is not given, set it to *"constrain"*.
-        1. Assert: _overflow_ is one of *"constrain"* or *"reject"*.
+        1. If _options_ is not given, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. If Type(_item_) is Object, then
           1. If _item_ has an [[InitializedTemporalYearMonth]] internal slot, then
             1. Return _item_.
           1. Let _calendar_ be ? GetOptionalTemporalCalendar(_item_).
           1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"month"*, *"year"* »).
           1. Let _fields_ be ? ToTemporalYearMonthFields(_item_, _fieldNames_).
-          1. Return ? YearMonthFromFields(_calendar_, _fields_, _overflow_, _constructor_).
+          1. Return ? YearMonthFromFields(_calendar_, _fields_, _constructor_, _options_).
+        1. Perform ? ToTemporalOverflow(_options_).
         1. Let _string_ be ? ToString(_item_).
         1. Let _result_ be ? ParseTemporalYearMonthString(_string_).
         1. If _result_.[[Day]] is *undefined*, then
diff --git a/spec/zoneddatetime.html b/spec/zoneddatetime.html
index c07883bb1b..db5f58f8af 100644
--- a/spec/zoneddatetime.html
+++ b/spec/zoneddatetime.html
@@ -69,12 +69,12 @@ <h1>Temporal.ZonedDateTime.from ( _item_ [ , _options_ ] )</h1>
       <emu-alg>
         1. Let _constructor_ be the *this* value.
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
-        1. Let _disambiguation_ be ? ToTemporalDisambiguation(_options_).
-        1. Let _offset_ be ? ToTemporalOffset(_options_).
         1. If Type(_item_) is Object and _item_ has an [[InitializedTemporalZonedDateTime]] internal slot, then
+          1. Perform ? ToTemporalOverflow(_options_).
+          1. Perform ? ToTemporalDisambiguation(_options_).
+          1. Perform ? ToTemporalOffset(_options_, *"reject"*).
           1. Return ? CreateTemporalZonedDateTimeFromStatic(_constructor_, _item_.[[Nanoseconds]], _item_.[[TimeZone]], _item_.[[Calendar]]).
-        1. Return ? ToTemporalZonedDateTime(_item_, _constructor_, _overflow_, _disambiguation_, _offset_).
+        1. Return ? ToTemporalZonedDateTime(_item_, _constructor_, _options_).
       </emu-alg>
     </emu-clause>
 
@@ -578,7 +578,6 @@ <h1>Temporal.ZonedDateTime.prototype.with ( _temporalZonedDateTimeLike_ [ , _opt
         1. Let _fieldNames_ be ? CalendarFields(_calendar_, « *"day"*, *"hour"*, *"microsecond"*, *"millisecond"*, *"minute"*, *"month"*, *"nanosecond"*, *"second"*, *"year"* »).
         1. Let _partialZonedDateTime_ be ? ToPartialZonedDateTime(_temporalZonedDateTimeLike_, _fieldNames_).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _disambiguation_ be ? ToTemporalDisambiguation(_options_).
         1. Let _offset_ be ? ToTemporalOffset(_options_, *"prefer"*).
         1. Let _timeZone_ be _zonedDateTime_.[[TimeZone]].
@@ -589,7 +588,7 @@ <h1>Temporal.ZonedDateTime.prototype.with ( _temporalZonedDateTimeLike_ [ , _opt
           1. Perform ? Set(_fields_, *"offset"*, _offsetString_).
         1. Else,
           1. Set _offsetString_ to ? Get(_fields_, *"offset"*).
-        1. Let _dateTimeResult_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _overflow_).
+        1. Let _dateTimeResult_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Let _offsetNanoseconds_ be ? ParseTimeZoneOffsetString(_offsetString_).
         1. Let _epochNanoseconds_ be ? InterpretTemporalZonedDateTimeOffset(_dateTimeResult_.[[Year]], _dateTimeResult_.[[Month]], _dateTimeResult_.[[Day]], _dateTimeResult_.[[Hour]], _dateTimeResult_.[[Minute]], _dateTimeResult_.[[Second]], _dateTimeResult_.[[Millisecond]], _dateTimeResult_.[[Microsecond]], _dateTimeResult_.[[Nanosecond]], _offsetNanoseconds_, _timeZone_, _disambiguation_, _offset_).
         1. Return ? CreateTemporalZonedDateTimeFromInstance(_zonedDateTime_, _epochNanoseconds_, _timeZone_, _calendar_).
@@ -679,10 +678,9 @@ <h1>Temporal.ZonedDateTime.prototype.add ( _temporalDurationLike_ [ , _options_
         1. Let _duration_ be ? ToLimitedTemporalDuration(_temporalDurationLike_, « »).
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _timeZone_ be _zonedDateTime_.[[TimeZone]].
         1. Let _calendar_ be _zonedDateTime_.[[Calendar]].
-        1. Let _epochNanoseconds_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _timeZone_, _calendar_, _duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], _overflow_).
+        1. Let _epochNanoseconds_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _timeZone_, _calendar_, _duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]], _options_).
         1. Return ? CreateTemporalZonedDateTimeFromInstance(_zonedDateTime_, _epochNanoseconds_, _timeZone_, _calendar_).
       </emu-alg>
     </emu-clause>
@@ -699,10 +697,9 @@ <h1>Temporal.ZonedDateTime.prototype.subtract ( _temporalDurationLike_ [ , _opti
         1. Let _duration_ be ? ToLimitedTemporalDuration(_temporalDurationLike_, « »).
         1. Perform ? RejectDurationSign(_duration_.[[Years]], _duration_.[[Months]], _duration_.[[Weeks]], _duration_.[[Days]], _duration_.[[Hours]], _duration_.[[Minutes]], _duration_.[[Seconds]], _duration_.[[Milliseconds]], _duration_.[[Microseconds]], _duration_.[[Nanoseconds]]).
         1. Set _options_ to ? NormalizeOptionsObject(_options_).
-        1. Let _overflow_ be ? ToTemporalOverflow(_options_).
         1. Let _timeZone_ be _zonedDateTime_.[[TimeZone]].
         1. Let _calendar_ be _zonedDateTime_.[[Calendar]].
-        1. Let _epochNanoseconds_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _timeZone_, _calendar_, −_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_duration_.[[Days]], −_duration_.[[Hours]], −_duration_.[[Minutes]], −_duration_.[[Seconds]], −_duration_.[[Milliseconds]], −_duration_.[[Microseconds]], −_duration_.[[Nanoseconds]], _overflow_).
+        1. Let _epochNanoseconds_ be ? AddZonedDateTime(_zonedDateTime_.[[Nanoseconds]], _timeZone_, _calendar_, −_duration_.[[Years]], −_duration_.[[Months]], −_duration_.[[Weeks]], −_duration_.[[Days]], −_duration_.[[Hours]], −_duration_.[[Minutes]], −_duration_.[[Seconds]], −_duration_.[[Milliseconds]], −_duration_.[[Microseconds]], −_duration_.[[Nanoseconds]], _options_).
         1. Return ? CreateTemporalZonedDateTimeFromInstance(_zonedDateTime_, _epochNanoseconds_, _timeZone_, _calendar_).
       </emu-alg>
     </emu-clause>
@@ -796,7 +793,7 @@ <h1>Temporal.ZonedDateTime.prototype.round ( _options_ )</h1>
         1. Let _dtStart_ be ? CreateTemporalDateTime(_temporalDateTime_.[[ISOYear]], _temporalDateTime_.[[ISOMonth]], _temporalDateTime_.[[ISODay]], 0, 0, 0, 0, 0, 0, _isoCalendar_).
         1. Let _instantStart_ be ? GetTemporalInstantFor(_timeZone_, _dtStart_, *"compatible"*).
         1. Let _startNs_ be _instantStart_.[[Nanoseconds]].
-        1. Let _endNs_ be ? AddZonedDateTime(_startNs_, _timeZone_, _calendar_, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, *"constrain"*).
+        1. Let _endNs_ be ? AddZonedDateTime(_startNs_, _timeZone_, _calendar_, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0).
         1. Let _dayLengthNs_ be _endNs_ − _startNs_.
         1. Let _roundResult_ be ? RoundDateTime(_temporalDateTime_.[[ISOYear]], _temporalDateTime_.[[ISOMonth]], _temporalDateTime_.[[ISODay]], _temporalDateTime_.[[ISOHour]], _temporalDateTime_.[[ISOMinute]], _temporalDateTime_.[[ISOSecond]], _temporalDateTime_.[[ISOMillisecond]], _temporalDateTime_.[[ISOMicrosecond]], _temporalDateTime_.[[ISONanosecond]], _roundingIncrement_, _smallestUnit_, _roundingMode_, _dayLengthNs_).
         1. Let _offsetNanoseconds_ be ? GetOffsetNanosecondsFor(_timeZone_, _instant_).
@@ -1107,18 +1104,13 @@ <h1>InterpretTemporalZonedDateTimeOffset ( _year_, _month_, _day_, _hour_, _minu
     </emu-clause>
 
     <emu-clause id="sec-temporal-totemporalzoneddatetime" aoid="ToTemporalZonedDateTime">
-      <h1>ToTemporalZonedDateTime ( _item_ [ , _constructor_ [ , _overflow_, _disambiguation_, _offset_ ] ] )</h1>
+      <h1>ToTemporalZonedDateTime ( _item_ [ , _constructor_ [ , _options_ ] ] )</h1>
       <p>
         The abstract operation ToTemporalZonedDateTime returns its argument _item_ if it is already a Temporal.ZonedDateTime instance, converts _item_ to a new Temporal.PlainDate instance if possible, and throws otherwise.
       </p>
       <emu-alg>
         1. If _constructor_ is not given, set it to %Temporal.ZonedDateTime%.
-        1. If _overflow_ is not given, set it to *"constrain"*.
-        1. Assert: _overflow_ is either *"constrain"* or *"reject"*.
-        1. If _disambiguation_ is not given, set it to *"compatible"*.
-        1. Assert: _disambiguation_ is either *"compatible"*, *"earlier"*, *"later"*, or *"reject"*.
-        1. If _offset_ is not given, set it to *"reject"*.
-        1. Assert: _offset_ is either *"use"*, *"ignore"*, *"prefer"*, or *"reject"*.
+        1. If _options_ is not given, set it to ! OrdinaryObjectCreate(%Object.prototype%).
         1. If Type(_item_) is Object, then
           1. If _item_ has an [[InitializedTemporalZonedDateTime]] internal slot, then
             1. Return _item_.
@@ -1129,8 +1121,9 @@ <h1>ToTemporalZonedDateTime ( _item_ [ , _constructor_ [ , _overflow_, _disambig
           1. Set _timeZone_ to ? ToTemporalTimeZone(_timeZone_).
           1. Let _offsetString_ be ? Get(_fields_, *"offset"*).
           1. If _offsetString_ is not *undefined*, set it to ? ToString(_offsetString_).
-          1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _item_, _overflow_).
+          1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _item_, _options_).
         1. Else,
+          1. Perform ? ToTemporalOverflow(_options_).
           1. Let _string_ be ? ToString(_item_).
           1. Let _result_ be ? ParseTemporalZonedDateTimeString(_string_).
           1. If _result_.[[TimeZoneName]] is *undefined*, throw a *RangeError* exception.
@@ -1138,6 +1131,8 @@ <h1>ToTemporalZonedDateTime ( _item_ [ , _constructor_ [ , _overflow_, _disambig
           1. Let _offsetString_ be _result_.[[TimeZoneOffsetString]].
           1. Let _calendar_ be ? ToOptionalTemporalCalendar(_result_.[[Calendar]]).
         1. Let _offsetNanoseconds_ be ? ParseTimeZoneOffsetString(_offsetString_).
+        1. Let _disambiguation_ be ? ToTemporalDisambiguation(_options_).
+        1. Let _offset_ be ? ToTemporalOffset(_options_, *"reject"*).
         1. Let _epochNanoseconds_ be ? InterpretTemporalZonedDateTimeOffset(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]], _result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]], _offsetNanoseconds_, _timeZone_, _disambiguation_, _offset_).
         1. Return ? CreateTemporalZonedDateTimeFromStatic(_constructor_, _epochNanoseconds_, _timeZone_, _calendar_).
       </emu-alg>
@@ -1349,7 +1344,7 @@ <h1>TemporalZonedDateTimeToString ( _zonedDateTime_, _precision_, _showCalendar_
     </emu-clause>
 
     <emu-clause id="sec-temporal-addzoneddatetime" aoid="AddZonedDateTime">
-      <h1>AddZonedDateTime ( _epochNanoseconds_, _timeZone_, _calendar_, _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, _overflow_ )</h1>
+      <h1>AddZonedDateTime ( _epochNanoseconds_, _timeZone_, _calendar_, _years_, _months_, _weeks_, _days_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_, _options_ )</h1>
       <p>
         The abstract operation AddZonedDateTime adds a duration in various units to a number of nanoseconds _epochNanoseconds_ since the Unix epoch, subject to the rules of _timeZone_ and _calendar_.
         As specified in <a href="https://tools.ietf.org/html/rfc5545">RFC 5545</a>, the date portion of the duration is added in calendar days, and the time portion is added in exact time.
@@ -1362,8 +1357,6 @@ <h1>AddZonedDateTime ( _epochNanoseconds_, _timeZone_, _calendar_, _years_, _mon
         1. Let _datePart_ be ? CreateTemporalDate(_temporalDateTime_.[[ISOYear]], _temporalDateTime_.[[ISOMonth]], _temporalDateTime_.[[ISODay]], _calendar_).
         1. Let _dateAdd_ be ? Get(_calendar_, *"dateAdd"*).
         1. Let _dateDuration_ be ? CreateTemporalDuration(_years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0).
-        1. Let _options_ be ! OrdinaryObjectCreate(%Object.prototype%).
-        1. Perform ! CreateDataPropertyOrThrow(_options_, *"overflow"*, _overflow_).
         1. Let _addedDate_ be ? Call(_dateAdd_, _calendar_, « _dateDuration_, _options_, %Temporal.PlainDate% »).
         1. Let _intermediateDateTime_ be ? CreateTemporalDateTime(_addedDate_.[[ISOYear]], _addedDate_.[[ISOMonth]], _addedDate_.[[ISODay]], _temporalDateTime_.[[ISOHour]], _temporalDateTime_.[[ISOMinute]], _temporalDateTime_.[[ISOSecond]], _temporalDateTime_.[[ISOMillisecond]], _temporalDateTime_.[[ISOMicrosecond]], _temporalDateTime_.[[ISONanosecond]], _calendar_).
         1. Let _intermediateInstant_ be ? GetTemporalInstantFor(_timeZone_, _intermediateDateTime_, *"compatible"*).
@@ -1372,7 +1365,7 @@ <h1>AddZonedDateTime ( _epochNanoseconds_, _timeZone_, _calendar_, _years_, _mon
     </emu-clause>
 
     <emu-clause id="sec-temporal-differencezoneddatetime" aoid="DifferenceZonedDateTime">
-      <h1>DifferenceZonedDateTime ( _ns1_, _ns2_, _timeZone_, _calendar_, _largestUnit_ )</h1>
+      <h1>DifferenceZonedDateTime ( _ns1_, _ns2_, _timeZone_, _calendar_, _largestUnit_ [ , _options_ ] )</h1>
       <p>
         The abstract operation DifferenceZonedDateTime computes the difference between two exact times expressed in nanoseconds since the Unix epoch, and balances the result so that there is no non-zero unit larger than _largestUnit_ in the result, taking calendar reckoning and time zone offset changes into account.
       </p>
@@ -1384,8 +1377,8 @@ <h1>DifferenceZonedDateTime ( _ns1_, _ns2_, _timeZone_, _calendar_, _largestUnit
         1. Let _startDateTime_ be ? GetTemporalDateTimeFor(_timeZone_, _startInstant_, _calendar_).
         1. Let _endInstant_ be ? CreateInstant(_ns2_).
         1. Let _endDateTime_ be ? GetTemporalDateTimeFor(_timeZone_, _endInstant_, _calendar_).
-        1. Let _dateDifference_ be ? DifferenceDateTime(_startDateTime_.[[ISOYear]], _startDateTime_.[[ISOMonth]], _startDateTime_.[[ISODay]], _startDateTime_.[[ISOHour]], _startDateTime_.[[ISOMinute]], _startDateTime_.[[ISOSecond]], _startDateTime_.[[ISOMillisecond]], _startDateTime_.[[ISOMicrosecond]], _startDateTime_.[[ISONanosecond]], _endDateTime_.[[ISOYear]], _endDateTime_.[[ISOMonth]], _endDateTime_.[[ISODay]], _endDateTime_.[[ISOHour]], _endDateTime_.[[ISOMinute]], _endDateTime_.[[ISOSecond]], _endDateTime_.[[ISOMillisecond]], _endDateTime_.[[ISOMicrosecond]], _endDateTime_.[[ISONanosecond]], _calendar_, _largestUnit_).
-        1. Let _intermediateNs_ be ? AddZonedDateTime(_ns1_, _timeZone_, _calendar_, _dateDifference_.[[Years]], _dateDifference_.[[Months]], _dateDifference_.[[Weeks]], 0, 0, 0, 0, 0, 0, 0, *"constrain"*).
+        1. Let _dateDifference_ be ? DifferenceDateTime(_startDateTime_.[[ISOYear]], _startDateTime_.[[ISOMonth]], _startDateTime_.[[ISODay]], _startDateTime_.[[ISOHour]], _startDateTime_.[[ISOMinute]], _startDateTime_.[[ISOSecond]], _startDateTime_.[[ISOMillisecond]], _startDateTime_.[[ISOMicrosecond]], _startDateTime_.[[ISONanosecond]], _endDateTime_.[[ISOYear]], _endDateTime_.[[ISOMonth]], _endDateTime_.[[ISODay]], _endDateTime_.[[ISOHour]], _endDateTime_.[[ISOMinute]], _endDateTime_.[[ISOSecond]], _endDateTime_.[[ISOMillisecond]], _endDateTime_.[[ISOMicrosecond]], _endDateTime_.[[ISONanosecond]], _calendar_, _largestUnit_, _options_).
+        1. Let _intermediateNs_ be ? AddZonedDateTime(_ns1_, _timeZone_, _calendar_, _dateDifference_.[[Years]], _dateDifference_.[[Months]], _dateDifference_.[[Weeks]], 0, 0, 0, 0, 0, 0, 0).
         1. Let _timeRemainderNs_ be _ns2_ − _intermediateNs_.
         1. Let _intermediate_ be ? CreateTemporalZonedDateTime(_intermediateNs_, _timeZone_, _calendar_).
         1. Let _result_ be ? NanosecondsToDays(_timeRemainderNs_, _intermediate_).
@@ -1418,15 +1411,15 @@ <h1>NanosecondsToDays ( _nanoseconds_, _relativeTo_ )</h1>
         1. Let _endDateTime_ be ? GetTemporalDateTimeFor(_timeZone_, _endInstant_, _calendar_).
         1. Let _dateDifference_ be ? DifferenceDateTime(_startDateTime_.[[ISOYear]], _startDateTime_.[[ISOMonth]], _startDateTime_.[[ISODay]], _startDateTime_.[[ISOHour]], _startDateTime_.[[ISOMinute]], _startDateTime_.[[ISOSecond]], _startDateTime_.[[ISOMillisecond]], _startDateTime_.[[ISOMicrosecond]], _startDateTime_.[[ISONanosecond]], _endDateTime_.[[ISOYear]], _endDateTime_.[[ISOMonth]], _endDateTime_.[[ISODay]], _endDateTime_.[[ISOHour]], _endDateTime_.[[ISOMinute]], _endDateTime_.[[ISOSecond]], _endDateTime_.[[ISOMillisecond]], _endDateTime_.[[ISOMicrosecond]], _endDateTime_.[[ISONanosecond]], _calendar_, *"days"*).
         1. Let _days_ be _dateDifference_.[[Days]].
-        1. Let _intermediateNs_ be ? AddZonedDateTime(_startNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, 0, 0, 0, 0, 0, 0, *"constrain"*).
+        1. Let _intermediateNs_ be ? AddZonedDateTime(_startNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, 0, 0, 0, 0, 0, 0).
         1. If _sign_ = 1, then
           1. Repeat, while _days_ &gt; 0 and _intermediateNs_ &gt; _endNs_,
             1. Set _days_ to _days_ − 1.
-            1. Set _intermediateNs_ to ? AddZonedDateTime(_startNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, 0, 0, 0, 0, 0, 0, *"constrain"*).
+            1. Set _intermediateNs_ to ? AddZonedDateTime(_startNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _days_, 0, 0, 0, 0, 0, 0).
         1. Set _nanoseconds_ to _endNs_ − _intermediateNs_.
         1. Let _done_ be *false*.
         1. Repeat, while _done_ is *false*,
-          1. Let _oneDayFartherNs_ be ? AddZonedDateTime(_intermediateNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _sign_, 0, 0, 0, 0, 0, 0, *"constrain"*).
+          1. Let _oneDayFartherNs_ be ? AddZonedDateTime(_intermediateNs_, _relativeTo_.[[TimeZone]], _relativeTo_.[[Calendar]], 0, 0, 0, _sign_, 0, 0, 0, 0, 0, 0).
           1. Set _dayLengthNs_ to _oneDayFartherNs_ − _intermediateNs_.
           1. If (_nanoseconds_ − _dayLengthNs_) × _sign_ ≥ 0, then
             1. Set _nanoseconds_ to _nanoseconds_ − _dayLengthNs_.