diff --git a/R/RcppExports.R b/R/RcppExports.R
index 130faad4f..3d81b1ac9 100644
--- a/R/RcppExports.R
+++ b/R/RcppExports.R
@@ -17,14 +17,14 @@ CPL_gdal_version <- function(what = "RELEASE_NAME") {
     .Call('_sf_CPL_gdal_version', PACKAGE = 'sf', what)
 }
 
-CPL_crs_parameters <- function(crs) {
-    .Call('_sf_CPL_crs_parameters', PACKAGE = 'sf', crs)
-}
-
 CPL_wkt_from_user_input <- function(input) {
     .Call('_sf_CPL_wkt_from_user_input', PACKAGE = 'sf', input)
 }
 
+CPL_crs_parameters <- function(crs) {
+    .Call('_sf_CPL_crs_parameters', PACKAGE = 'sf', crs)
+}
+
 CPL_crs_equivalent <- function(crs1, crs2) {
     .Call('_sf_CPL_crs_equivalent', PACKAGE = 'sf', crs1, crs2)
 }
diff --git a/R/crs.R b/R/crs.R
index 3d9e93c51..dca9bb473 100644
--- a/R/crs.R
+++ b/R/crs.R
@@ -75,11 +75,24 @@ st_crs.character = function(x, ...) {
 	}
 }
 
+fix_crs = function(x) {
+	if (all(c("epsg", "proj4string") %in% names(x))) {
+		# warning("old-style crs object detected; please recreate object with a modern sf::st_crs()")
+		x = unclass(x)
+		if (!is.na(x$epsg))
+			st_crs(x$epsg)
+		else
+			st_crs(x$proj4string)
+	} else
+		x
+}
+
+
 #' @name st_crs
 #' @param parameters logical; \code{FALSE} by default; if \code{TRUE} return a list of coordinate reference system parameters, with named elements \code{SemiMajor}, \code{InvFlattening}, \code{units_gdal}, \code{IsVertical}, \code{WktPretty}, and \code{Wkt}
 #' @export
 st_crs.sfc = function(x, ..., parameters = FALSE) {
-	crs = attr(x, "crs")
+	crs = fix_crs(attr(x, "crs"))
 	if (parameters) {
 		if (is.na(crs))
 			list()
@@ -299,7 +312,7 @@ is.na.crs = function(x) {
 		x = st_crs(x[["proj4string"]]) # FIXME: should this be only for some transition period? Add test?
 	}
 	if (is.na(x))
-		NA
+		NA_character_
 	else if (is.numeric(name) || name %in% names(x))
 		x[[name]]
 	else {
diff --git a/R/sfc.R b/R/sfc.R
index 75c291e12..37f1a5cdb 100644
--- a/R/sfc.R
+++ b/R/sfc.R
@@ -215,8 +215,8 @@ print.sfc = function(x, ..., n = 5L, what = "Geometry set for", append = "") {
 			cat(paste0("geographic CRS: ", p$Name, "\n"))
 		else
 			cat(paste0("projected CRS:  ", p$Name, "\n"))
-		if (!is.na(crs$epsg))
-			cat(paste0("epsg (SRID):    ", crs$epsg, "\n"))
+#		if (!is.na(crs$epsg))
+#			cat(paste0("epsg (SRID):    ", crs$epsg, "\n"))
 	}
 	if (attr(x, "precision") != 0.0) {
 		cat(paste0("precision:      "))
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
index df21b83f5..3c9f21e03 100644
--- a/src/RcppExports.cpp
+++ b/src/RcppExports.cpp
@@ -49,25 +49,25 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
-// CPL_crs_parameters
-Rcpp::List CPL_crs_parameters(Rcpp::List crs);
-RcppExport SEXP _sf_CPL_crs_parameters(SEXP crsSEXP) {
+// CPL_wkt_from_user_input
+Rcpp::CharacterVector CPL_wkt_from_user_input(Rcpp::CharacterVector input);
+RcppExport SEXP _sf_CPL_wkt_from_user_input(SEXP inputSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
-    Rcpp::traits::input_parameter< Rcpp::List >::type crs(crsSEXP);
-    rcpp_result_gen = Rcpp::wrap(CPL_crs_parameters(crs));
+    Rcpp::traits::input_parameter< Rcpp::CharacterVector >::type input(inputSEXP);
+    rcpp_result_gen = Rcpp::wrap(CPL_wkt_from_user_input(input));
     return rcpp_result_gen;
 END_RCPP
 }
-// CPL_wkt_from_user_input
-Rcpp::CharacterVector CPL_wkt_from_user_input(Rcpp::CharacterVector input);
-RcppExport SEXP _sf_CPL_wkt_from_user_input(SEXP inputSEXP) {
+// CPL_crs_parameters
+Rcpp::List CPL_crs_parameters(Rcpp::List crs);
+RcppExport SEXP _sf_CPL_crs_parameters(SEXP crsSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
-    Rcpp::traits::input_parameter< Rcpp::CharacterVector >::type input(inputSEXP);
-    rcpp_result_gen = Rcpp::wrap(CPL_wkt_from_user_input(input));
+    Rcpp::traits::input_parameter< Rcpp::List >::type crs(crsSEXP);
+    rcpp_result_gen = Rcpp::wrap(CPL_crs_parameters(crs));
     return rcpp_result_gen;
 END_RCPP
 }
@@ -1119,8 +1119,8 @@ static const R_CallMethodDef CallEntries[] = {
     {"_sf_CPL_gdal_init", (DL_FUNC) &_sf_CPL_gdal_init, 0},
     {"_sf_CPL_gdal_cleanup_all", (DL_FUNC) &_sf_CPL_gdal_cleanup_all, 0},
     {"_sf_CPL_gdal_version", (DL_FUNC) &_sf_CPL_gdal_version, 1},
-    {"_sf_CPL_crs_parameters", (DL_FUNC) &_sf_CPL_crs_parameters, 1},
     {"_sf_CPL_wkt_from_user_input", (DL_FUNC) &_sf_CPL_wkt_from_user_input, 1},
+    {"_sf_CPL_crs_parameters", (DL_FUNC) &_sf_CPL_crs_parameters, 1},
     {"_sf_CPL_crs_equivalent", (DL_FUNC) &_sf_CPL_crs_equivalent, 2},
     {"_sf_CPL_crs_from_input", (DL_FUNC) &_sf_CPL_crs_from_input, 1},
     {"_sf_CPL_roundtrip", (DL_FUNC) &_sf_CPL_roundtrip, 1},
diff --git a/src/gdal.cpp b/src/gdal.cpp
index 6748353db..7a06061ea 100644
--- a/src/gdal.cpp
+++ b/src/gdal.cpp
@@ -116,7 +116,51 @@ void handle_error(OGRErr err) {
 	}
 }
 
+Rcpp::CharacterVector wkt_from_spatial_reference(OGRSpatialReference *srs) { // FIXME: add options?
+	char *cp;
+#if GDAL_VERSION_MAJOR >= 3
+	const char *options[3] = { "MULTILINE=YES", "FORMAT=WKT2", NULL };
+	OGRErr err = srs->exportToWkt(&cp, options);
+#else
+	OGRErr err = srs->exportToPrettyWkt(&cp);
+#endif
+	if (err != OGRERR_NONE)
+		Rcpp::stop("OGR error: cannot export to WKT");
+	Rcpp::CharacterVector out(cp);
+	CPLFree(cp);
+	return out;
+}
+
+// [[Rcpp::export]]
+Rcpp::CharacterVector CPL_wkt_from_user_input(Rcpp::CharacterVector input) {
+	OGRSpatialReference *srs = new OGRSpatialReference;
+	srs = handle_axis_order(srs);
+	handle_error(srs->SetFromUserInput((const char *) input[0]));
+	Rcpp::CharacterVector out = wkt_from_spatial_reference(srs);
+	delete srs;
+	return(out);
+}
+
+Rcpp::List fix_old_style(Rcpp::List crs) {
+	Rcpp::CharacterVector n = crs.attr("names");
+	if (n[0] == "epsg") { // create new:
+		Rcpp::List ret(2);
+		Rcpp::CharacterVector proj4string = crs[1];
+		ret[0] = proj4string[0];
+		ret[1] = CPL_wkt_from_user_input(proj4string);
+		Rcpp::CharacterVector names(2);
+		names(0) = "input";
+		names(1) = "wkt";
+		ret.attr("names") = names;
+		ret.attr("class") = "crs";
+		return ret;
+	} else
+		return crs;
+}
+
 OGRSpatialReference *OGRSrs_from_crs(Rcpp::List crs) {
+	// fix old-style crs:
+	crs = fix_old_style(crs);
 	OGRSpatialReference *dest = NULL;
 	Rcpp::CharacterVector wkt = crs[1];
 	if (! Rcpp::CharacterVector::is_na(wkt[0])) {
@@ -224,31 +268,6 @@ int epsg_from_crs(Rcpp::List crs) {
 		return(NA_INTEGER);
 }
 
-Rcpp::CharacterVector wkt_from_spatial_reference(OGRSpatialReference *srs) { // FIXME: add options?
-	char *cp;
-#if GDAL_VERSION_MAJOR >= 3
-	const char *options[3] = { "MULTILINE=YES", "FORMAT=WKT2", NULL };
-	OGRErr err = srs->exportToWkt(&cp, options);
-#else
-	OGRErr err = srs->exportToPrettyWkt(&cp);
-#endif
-	if (err != OGRERR_NONE)
-		Rcpp::stop("OGR error: cannot export to WKT");
-	Rcpp::CharacterVector out(cp);
-	CPLFree(cp);
-	return out;
-}
-
-// [[Rcpp::export]]
-Rcpp::CharacterVector CPL_wkt_from_user_input(Rcpp::CharacterVector input) {
-	OGRSpatialReference *srs = new OGRSpatialReference;
-	srs = handle_axis_order(srs);
-	handle_error(srs->SetFromUserInput((const char *) input[0]));
-	Rcpp::CharacterVector out = wkt_from_spatial_reference(srs);
-	delete srs;
-	return(out);
-}
-
 // [[Rcpp::export]]
 Rcpp::LogicalVector CPL_crs_equivalent(Rcpp::List crs1, Rcpp::List crs2) {