[stevekemp]

No, I always upgrade to the latest release when I spot it, but I don't try nightlies or anything other than releases.

I take a backup of ~/.mozilla and just download the new binaries to /opt/firefox. (Well I download and update a symlink.)

[callahad]

We might be resolving symlinks to their physical paths, making each download look like a new install. If so, the nixpkgs issue I mentioned above is probably more relevant than expected.

I'm not entirely certain, but if you want to source dive, nsXREDirProvider::GetInstallHash is a good place to start: https://searchfox.org/mozilla-central/rev/6c9f60f8cc064a1005...