Reply to myselves and all others in same situation:
- open adb shell to the phone with the new installation
- Go to the Authenticator NG folder: cd ~/.config/authenticator-ng.dobey
- Rename the current config file, in case you want it back later: mv authenticator.conf [newname]
- exit ADB
- Push your saved authenticator.conf to the reight location on the new installation: adb push [local path/authenticator.conf] /home/phablet/.config/authenticator-ng.dobey