diff --git a/lib/config/options/index.ts b/lib/config/options/index.ts
index fa6c284b62823d..34d904b39c20b8 100644
--- a/lib/config/options/index.ts
+++ b/lib/config/options/index.ts
@@ -2213,6 +2213,7 @@ const options: RenovateOptions[] = [
     description:
       'User-facing strings pertaining to the PR comment that gets posted when a PR is closed.',
     type: 'object',
+    freeChoice: true,
     default: {
       ignoreTopic: 'Renovate Ignore Notification',
       ignoreMajor: