Just download 'Firefox Preview' in the Play Store. That's the version which will eventually replace the old one.

I want to avoid the play store. So I was looking for an official apk source.

From https://github.com/mozilla-mobile/fenix/issues/8350#issuecom...

> We do a staged roll-out before publishing APKs. As far as I'm aware neither are at 100% which is a requirement for posting the builds. The APK is available from automation in the meantime if you want: https://firefox-ci-tc.services.mozilla.com/tasks/index/proje...