The merge queue no longer rebases fork pull requests on behalf of an account

Updating a queued pull request that comes from a fork with update_method: rebase and an update_bot_account required Mergify to impersonate that account and force-push the fork’s branch, because GitHub refuses an OAuth token on its rebase API for a fork. That capability was deprecated for removal on July 1, 2026, and it has now been removed.

Affected pull requests are now refused when they are queued rather than while they are being updated, so one of them never embarks and never holds up the pull requests behind it. The check run names the removal and what to change.

To keep queueing pull requests from forks, unset update_bot_account on the queue: with no account to impersonate, the update rebases through GitHub’s API as Mergify. On a queue that does not merge with fast-forward, update_method: merge works too. Queues that run their checks on a draft pull request are not affected, and neither is update_method: rebase without an update_bot_account.