How can I use the owner mode on my new smartphone?
The unlocked owner mode is linked to your Apple ID or Google account.
Once installed on a new phone or tablet, you can easily reactivate the host mode by simply clicking "Restore purchases".
Tap the in the top left corner to open the „About Herein!“. Here you tap on „For restaurateurs & shop owners“. You can now restore previously made purchases by tapping on the "restore purchases".

Further details on restoring in-app purchases can be found on the corresponding help pages of Apple and Google.