PSA: do not update #ntfy to version 1.17.0 from #fdroid. It is a pre release that will crash ntfy on startup https://github.com/binwiederhier/ntfy-android/issues/127
F-Droid released 1.17.0 which crashes on startup when reading the internal database · Issue #127 · binwiederhier/ntfy-android

It looks like F-Droid build a pre-release (?) with 1.17.0 that crashes on startup when reading the internal database. From their build metadata it looks like they've bumped to 1.17.8 since, I hope ...

GitHub
@returntrip thanks, too late for me.
Always well prepared: neobackup is my friend ;-)
@gischpelino I have no backup.... Will see how I can sort this :)
@returntrip for the future: use the export of all settings and data from ntfy settings. That's the best way and does not need rooting the device. From time to time or after adding subscribed topics is enougth to get all topics back.