GitHub is introducing a new "app installation" token format with substantially longer tokens

[jmehnle]

GitHub is introducing a new "app installation" token format with substantially longer tokens. Would this break compatibility with GitHubKit?

https://github.blog/changelog/2026-04-24-notice-about-upcoming-new-format-for-github-app-installation-tokens/

They're also providing a header to force either the old format or the new format as a migration mechanism:

https://github.blog/changelog/2026-05-15-github-app-installation-tokens-per-request-override-header/

[yanyongyu]

GitHubKit doesn't care about the token's format. I'll make a test.

[yanyongyu]

I've made a test with "X-GitHub-Stateless-S2S-Token": "enabled" header added. Everything works correctly.