diff --git a/ext/pgsql/config.m4 b/ext/pgsql/config.m4
index 07c848ca688b1..b7a5ebb8110bb 100644
--- a/ext/pgsql/config.m4
+++ b/ext/pgsql/config.m4
@@ -65,7 +65,6 @@ if test "$PHP_PGSQL" != "no"; then
   old_CFLAGS=$CFLAGS
   CFLAGS="$CFLAGS -I$PGSQL_INCLUDE"
   AC_CHECK_LIB(pq, PQlibVersion,, AC_MSG_ERROR([Unable to build the PostgreSQL extension: at least libpq 9.1 is required]))
-  AC_CHECK_LIB(pq, pg_encoding_to_char,AC_DEFINE(HAVE_PGSQL_WITH_MULTIBYTE_SUPPORT,1,[Whether libpq is compiled with --enable-multibyte]))
   AC_CHECK_LIB(pq, lo_truncate64, AC_DEFINE(HAVE_PG_LO64,1,[PostgreSQL 9.3 or later]))
   AC_CHECK_LIB(pq, PQsetErrorContextVisibility, AC_DEFINE(HAVE_PG_CONTEXT_VISIBILITY,1,[PostgreSQL 9.6 or later]))
   AC_CHECK_LIB(pq, PQresultMemorySize, AC_DEFINE(HAVE_PG_RESULT_MEMORY_SIZE,1,[PostgreSQL 12 or later]))
diff --git a/ext/pgsql/config.w32 b/ext/pgsql/config.w32
index 603239c43144d..7ad46fd8892e6 100644
--- a/ext/pgsql/config.w32
+++ b/ext/pgsql/config.w32
@@ -7,7 +7,7 @@ if (PHP_PGSQL != "no") {
 		CHECK_HEADER_ADD_INCLUDE("libpq-fe.h", "CFLAGS_PGSQL", PHP_PGSQL + "\\include;" + PHP_PHP_BUILD + "\\include\\pgsql;" + PHP_PHP_BUILD + "\\include\\libpq;" + PHP_PGSQL)) {
 		EXTENSION("pgsql", "pgsql.c", PHP_PGSQL_SHARED, "/DZEND_ENABLE_STATIC_TSRMLS_CACHE=1");
 		AC_DEFINE('HAVE_PGSQL', 1, 'Have PostgreSQL library');
-		ADD_FLAG("CFLAGS_PGSQL", "/D PGSQL_EXPORTS /D HAVE_PGSQL_WITH_MULTIBYTE_SUPPORT" + (X64 ? " /D HAVE_PG_LO64" : "") + " ");
+		ADD_FLAG("CFLAGS_PGSQL", "/D PGSQL_EXPORTS" + (X64 ? " /D HAVE_PG_LO64" : "") + " ");
 		ADD_EXTENSION_DEP('pgsql', 'pcre');
 	} else {
 		WARNING("pgsql not enabled; libraries and headers not found");
diff --git a/ext/pgsql/pgsql.c b/ext/pgsql/pgsql.c
index 5d23741b0c065..09328c0d921a6 100644
--- a/ext/pgsql/pgsql.c
+++ b/ext/pgsql/pgsql.c
@@ -278,10 +278,6 @@ static void pgsql_lob_free_obj(zend_object *obj)
 
 /* Compatibility definitions */
 
-#ifndef HAVE_PGSQL_WITH_MULTIBYTE_SUPPORT
-#define pg_encoding_to_char(x) "SQL_ASCII"
-#endif
-
 static zend_string *_php_pgsql_trim_message(const char *message)
 {
 	size_t i = strlen(message);
@@ -601,11 +597,7 @@ PHP_MINFO_FUNCTION(pgsql)
 	php_info_print_table_start();
 	php_info_print_table_row(2, "PostgreSQL Support", "enabled");
 	php_info_print_table_row(2, "PostgreSQL (libpq) Version", pgsql_libpq_version);
-#ifdef HAVE_PGSQL_WITH_MULTIBYTE_SUPPORT
 	php_info_print_table_row(2, "Multibyte character support", "enabled");
-#else
-	php_info_print_table_row(2, "Multibyte character support", "disabled");
-#endif
 	snprintf(buf, sizeof(buf), ZEND_LONG_FMT, PGG(num_persistent));
 	php_info_print_table_row(2, "Active Persistent Links", buf);
 	snprintf(buf, sizeof(buf), ZEND_LONG_FMT, PGG(num_links));
diff --git a/ext/pgsql/php_pgsql.h b/ext/pgsql/php_pgsql.h
index b9a5fec11d541..5e661e1065f91 100644
--- a/ext/pgsql/php_pgsql.h
+++ b/ext/pgsql/php_pgsql.h
@@ -48,10 +48,6 @@ extern zend_module_entry pgsql_module_entry;
 # endif
 #endif
 
-#ifdef HAVE_PGSQL_WITH_MULTIBYTE_SUPPORT
-const char * pg_encoding_to_char(int encoding);
-#endif
-
 PHP_MINIT_FUNCTION(pgsql);
 PHP_MSHUTDOWN_FUNCTION(pgsql);
 PHP_RINIT_FUNCTION(pgsql);