diff --git a/tests/runtests.pl b/tests/runtests.pl
index 61949614b9..a326fc37b6 100755
--- a/tests/runtests.pl
+++ b/tests/runtests.pl
@@ -2539,6 +2539,10 @@ while(@ARGV) {
             $jobs = $1;
         }
     }
+    elsif($ARGV[0] eq "-k") {  # delete this check after December 2026
+        print "Option -k became always-on in 7.65.2 (2019) and now a no-op. Delete it to continue.\n";
+        exit;
+    }
     elsif($ARGV[0] eq "-r") {
         # run time statistics needs Time::HiRes
         if($Time::HiRes::VERSION) {