The most secure connection status for synchronizing and restoring is to have your TimeBlocks account connected.
To do this, go to the TimeBlocks menu - Connect.
Here you can also link external calendar accounts that you use frequently (e.g. Google or iOS calendars).
The TimeBlocks service manages both the data in the TimeBlocks account as well as the additional attributes (e.g. color, etc.) added via external calendars linked to the TimeBlocks app, which also can be restored on the new devices when you replace your old one. This is only possible when you link your TimeBlocks account to the external calendar account.
So please try it and ask if you have any difficulties in the process.