Firefox just got upgraded to version 57. Unfortunately this version breaks compatibility with an add-on that I rely on. Until support for add-ons improves, I want to stick with a version that works.
It's too late to block the upgrade, now I need to downgrade. I have an APK of the old version, downloaded from apkmirror (though I would prefer an official source of I could find one). But how do I install it without losing my settings?
After some fumbling with methods that rejected downgrades, I found a way:
adb install -r -d org.mozilla.firefox_56.*.apk
This did downgrade, but then Firefox systematically crashed on startup.
I guess it's too late for me --- I uninstalled and reinstalled, leaving I had to reinstall my add-ons, bookmarks, saved passwords, etc. But I'm sure I'm not the only one who got bien or is about to get bitten by the Quantum update. So how can one downgrade Firefox without losing settings?