diff --git a/example/lib/main.dart b/example/lib/main.dart
index 4e4d618..81a613d 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -191,7 +191,7 @@ class MySampleState extends State<MySample> {
                             shape: RoundedRectangleBorder(
                               borderRadius: BorderRadius.circular(8.0),
                             ),
-                            primary: const Color(0xff1b447b),
+                            backgroundColor: const Color(0xff1b447b),
                           ),
                           child: Container(
                             margin: const EdgeInsets.all(12),
diff --git a/lib/credit_card_form.dart b/lib/credit_card_form.dart
index e8f5d06..ee4a9d0 100644
--- a/lib/credit_card_form.dart
+++ b/lib/credit_card_form.dart
@@ -1,8 +1,5 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_credit_card/flutter_credit_card.dart';
-import 'package:jiffy/jiffy.dart';
-
-import 'flutter_credit_card.dart';
 
 class CreditCardForm extends StatefulWidget {
   const CreditCardForm({
@@ -114,7 +111,7 @@ class _CreditCardFormState extends State<CreditCardForm> {
     super.initState();
 
     createCreditCardModel();
-      
+
     _cardNumberController.text = widget.cardNumber;
     _expiryDateController.text = widget.expiryDate;
     _cardHolderNameController.text = widget.cardHolderName;
@@ -248,8 +245,11 @@ class _CreditCardFormState extends State<CreditCardForm> {
                           final List<String> date = value.split(RegExp(r'/'));
                           final int month = int.parse(date.first);
                           final int year = int.parse('20${date.last}');
-                          final int lastDayofMonth = DateTime(year, Jiffy( DateTime(year,month)).add(months: 1).month, 0 ).day;
-                          final DateTime cardDate = DateTime(year, month, lastDayofMonth);
+                          final int lastDayOfMonth = month < 12
+                              ? DateTime(year, month + 1, 0).day
+                              : DateTime(year + 1, 1, 0).day;
+                          final DateTime cardDate = DateTime(
+                              year, month, lastDayOfMonth, 23, 59, 59, 999);
 
                           if (cardDate.isBefore(now) ||
                               month > 12 ||
diff --git a/pubspec.lock b/pubspec.lock
deleted file mode 100644
index 290a5eb..0000000
--- a/pubspec.lock
+++ /dev/null
@@ -1,160 +0,0 @@
-# Generated by pub
-# See https://dart.dev/tools/pub/glossary#lockfile
-packages:
-  async:
-    dependency: transitive
-    description:
-      name: async
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.6.1"
-  boolean_selector:
-    dependency: transitive
-    description:
-      name: boolean_selector
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.0"
-  characters:
-    dependency: transitive
-    description:
-      name: characters
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.1.0"
-  charcode:
-    dependency: transitive
-    description:
-      name: charcode
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.2.0"
-  clock:
-    dependency: transitive
-    description:
-      name: clock
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.1.0"
-  collection:
-    dependency: transitive
-    description:
-      name: collection
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.15.0"
-  fake_async:
-    dependency: transitive
-    description:
-      name: fake_async
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.2.0"
-  flutter:
-    dependency: "direct main"
-    description: flutter
-    source: sdk
-    version: "0.0.0"
-  flutter_test:
-    dependency: "direct dev"
-    description: flutter
-    source: sdk
-    version: "0.0.0"
-  intl:
-    dependency: transitive
-    description:
-      name: intl
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.17.0"
-  jiffy:
-    dependency: "direct main"
-    description:
-      name: jiffy
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "4.1.0"
-  matcher:
-    dependency: transitive
-    description:
-      name: matcher
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.12.10"
-  meta:
-    dependency: transitive
-    description:
-      name: meta
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.0"
-  path:
-    dependency: transitive
-    description:
-      name: path
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.8.0"
-  sky_engine:
-    dependency: transitive
-    description: flutter
-    source: sdk
-    version: "0.0.99"
-  source_span:
-    dependency: transitive
-    description:
-      name: source_span
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.8.1"
-  stack_trace:
-    dependency: transitive
-    description:
-      name: stack_trace
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.10.0"
-  stream_channel:
-    dependency: transitive
-    description:
-      name: stream_channel
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.0"
-  string_scanner:
-    dependency: transitive
-    description:
-      name: string_scanner
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.1.0"
-  term_glyph:
-    dependency: transitive
-    description:
-      name: term_glyph
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.2.0"
-  test_api:
-    dependency: transitive
-    description:
-      name: test_api
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.3.0"
-  typed_data:
-    dependency: transitive
-    description:
-      name: typed_data
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.0"
-  vector_math:
-    dependency: transitive
-    description:
-      name: vector_math
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.0"
-sdks:
-  dart: ">=2.12.0 <3.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 75c4b2f..df8cc6b 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -10,7 +10,6 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  jiffy: ^4.1.0
 
 dev_dependencies:
   flutter_test: