diff --git a/tests/specs/serve/request_signal_streaming/main.out b/tests/specs/serve/request_signal_streaming/main.out
index 289f53a216a603..6a206b2fd408fa 100644
--- a/tests/specs/serve/request_signal_streaming/main.out
+++ b/tests/specs/serve/request_signal_streaming/main.out
@@ -1,3 +1,4 @@
+Deno.serve: request.signal aborts on successful responses (legacy behavior, see https://github.com/denoland/deno/issues/29111). Move cleanup to the handler's return path, or opt in to the new behavior with --unstable-no-legacy-abort. See https://docs.deno.com/runtime/reference/migrate-deprecations/
 body: chunk1;chunk2;chunk3;chunk4;chunk5;
 aborted during stream: false
 aborted after completion: true