@xav You can try installing it over the other version. Of course, you should always have backups of everything
Update: But after installing over the other version, you have to
- unselect the address book in DAVdroid,
- force sync and wait until sync is finished (address book is gone),
- select the address book again,
- force sync again.
Otherwise the questionable contacts are not imported again and the new logic won’t be applied. So this is why I recommend to uninstall it – it just makes things easier, and setting up the account again shouldn’t take more than a few seconds.