diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6cd190ac1a..42e96b96f2 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1520,7 +1520,7 @@ include_dir 'conf.d'
         It does not need to be the same curve used by the server's Elliptic
         Curve key.  This parameter can only be set in the
         <filename>postgresql.conf</filename> file or on the server command line.
-        The default is <literal>prime256v1</literal>.
+        The default is <literal>X25519:prime256v1</literal>.
        </para>
 
        <para>
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 0d3ebf06a9..4984d12606 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4768,7 +4768,7 @@ struct config_string ConfigureNamesString[] =
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
-		"prime256v1",
+		"X25519:prime256v1",
 #else
 		"none",
 #endif
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 8ac2beb177..db44fa563b 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -114,7 +114,7 @@
 #ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL'	# allowed TLSv1.2 ciphers
 #ssl_tls13_ciphers = ''	# allowed TLSv1.3 cipher suites, blank for default
 #ssl_prefer_server_ciphers = on
-#ssl_groups = 'prime256v1'
+#ssl_groups = 'X25519:prime256v1'
 #ssl_min_protocol_version = 'TLSv1.2'
 #ssl_max_protocol_version = ''
 #ssl_dh_params_file = ''
diff --git a/src/test/ssl/t/SSL/Server.pm b/src/test/ssl/t/SSL/Server.pm
index 447469d893..1427741841 100644
--- a/src/test/ssl/t/SSL/Server.pm
+++ b/src/test/ssl/t/SSL/Server.pm
@@ -301,7 +301,7 @@ sub switch_server_cert
 	$node->append_conf('sslconfig.conf', "ssl=on");
 	$node->append_conf('sslconfig.conf', $backend->set_server_cert(\%params));
 	# use lists of ECDH curves and cipher suites for syntax testing
-	$node->append_conf('sslconfig.conf', 'ssl_groups=prime256v1:secp521r1');
+	$node->append_conf('sslconfig.conf', 'ssl_groups=X25519:prime256v1:secp521r1');
 	$node->append_conf('sslconfig.conf',
 		'ssl_tls13_ciphers=TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256');