I’ve just updated f-droid app from 1.15.6 to 1.16 and facing again probably those old annoying bug with signature incompability, but now it’s definitely on f-droid’s side, not on microg repo.
By the way, app can’t be downgraded back due to the “Error -25: new package has older version code than currently installed package”. But seems like it’s caused by LOS4microg ROM in my case, in which f-droid is preinstalled as a system app.
That’s an Android feature, not sure any ROM in the recent history allowed downgrades.
O.K. If so, but what’s the solution? wait for the new build of f-droid?
Picture App Manager Signature of the installed microg pls?
It’s from official microg repo, was installed and updated from f-droid last times without any problems (except one bug in October, mentioned earlier).
Indeed it is 
Any suggestions?
After updating f-droid on another device to the latest stable 1.16.1 ver. I get the same issue with sudden microg “incompability”, but it’s definitely some weird bug due to the new build of f-droid.
This thing you need to find out: how does your ROM implements signature spoofing. Then you can make your MicroG work right.
The most recent signer bug has nothing to do with microG but broke with some changes (probably this → https://github.com/f-droid/fdroidclient/blob/master/CHANGELOG.md#116-alpha0-2022-12-02) introduced in F-Droid 1.16
I just came across an old R/11 emulator image w/ microG in my Android Studio installation (for a completely different reason) and decided to try to reproduce this by updating the F-Droid client incremental until things break:
Version is left to right 1.14 → 1.15.6 → 1.16 → 1.16.1 (latest)
I also enabled Force old index format in 1.16.1 and updated the repos but to no avail.
Downgrading F-Droid to 1.15.6 (from https://f-droid.org/repo/org.fdroid.fdroid_1015056.apk) using adb
adb install -r -d org.fdroid.fdroid_1015056.apk
fixes this, tho you lose all your custom repos, probably for the same reason.
Cheers
@defkev this message would be super useful to have as an issue, so we can track it: Issues · F-Droid / Client · GitLab