Switching between two different FP-Open-Versions or alternativ FPOS- hiding data from Google

[AnotherElk]

@Ingo

I don’t know what happens if the contacts were stored on the phone and the Google apps are installed later

At least back when I used Open GApps, the syncing to Google was enabled by default, so one of the first things to do after installing Open GApps was to disable syncing for the Google account.