Switch to the simplex.apk (64 bit) GitHub release and keep it updated via Obtainium: https://github.com/ImranR98/Obtainium
If you were using f-droid.org release then you'll need to export database and uninstall the app first as they have different signing key, if you were using app.simplex.chat repo then it's the same and the GitHub release will install over it.
? I loaded the fdroid version of the app around a year ago. #simplex #asknostr #grapheneos