When an open upgrade PR already exists for a recipe (branch upgrade-*), push the new work onto ITS branch and update+re-test that PR — one evolving upgrade PR per recipe instead of spawning a second parallel PR. Only open a fresh upgrade-<version> PR when none exists. Unrelated open PRs (e.g. backup fixes) are still never touched; merged-upstream PRs still close. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>