The update-progress page declared completion on two consecutive 200s from
the /up health route. But the OLD container keeps answering /up 200
throughout the minutes-long rebuild, so the page redirected prematurely
back into the teardown → 502 / white screen.
Now the page polls a lightweight public /version.json probe and finishes
only when the running version has actually moved past the pre-update one
(passed as ?from=), or after an observed down→up cycle for a same-version
redeploy. The 10-minute timeout + manual-reload fallback are unchanged.
- routes/web.php: add public GET /version.json; sanitise+pass ?from= to the view
- Versions/Index.php: include the installed version as ?from= in the redirect
- update-progress.blade.php: version-gated completion (fromVersion/sawDown)
- UpdateProgressTest: probe endpoint, embedded baseline, from-sanitisation, no /up poll
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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