diff --git a/PGBuild/Modules/TestUpgradeXversion.pm b/PGBuild/Modules/TestUpgradeXversion.pm
index 8bc226f..bb9e560 100644
--- a/PGBuild/Modules/TestUpgradeXversion.pm
+++ b/PGBuild/Modules/TestUpgradeXversion.pm
@@ -434,6 +434,38 @@ sub test_upgrade    ## no critic (Subroutines::ProhibitManyArgs)
 		}
 	}
 
+	# operators not supported from release 14
+	if (   ($this_branch gt 'REL_13_STABLE' || $this_branch eq 'HEAD')
+		&& ($oversion le 'REL_13_STABLE' && $oversion ne 'HEAD'))
+	{
+		my $prstmt = join(';',
+						  'drop operator if exists #@# (bigint,NONE)',
+						  'drop operator if exists #%# (bigint,NONE)',
+						  'drop operator if exists !=- (bigint,NONE)',
+						  'drop operator if exists #@%# (bigint,NONE)');
+
+		system( "$other_branch/inst/bin/psql -X -e "
+				  . " -c '$prstmt' "
+				  . "regression "
+				  . ">> '$upgrade_loc/$oversion-copy.log' 2>&1");
+		return if $?;
+
+		if ($oversion le 'REL9_4_STABLE')
+		{
+			# this is fixed in 9.5 and later
+			$prstmt = join(';',
+						   'drop operator @#@ (NONE, bigint)',
+						   'CREATE OPERATOR @#@ (' .
+							 'PROCEDURE = factorial, ' .
+							 'RIGHTARG = bigint )');
+			system( "$other_branch/inst/bin/psql -X -e "
+					  . " -c '$prstmt' "
+					  . "regression "
+					  . ">> '$upgrade_loc/$oversion-copy.log' 2>&1");
+			return if $?;
+		}
+	}
+
 	my $extra_digits = "";
 
 	if (   $oversion ne 'HEAD'