In DMD² you can go to Global Settings (cog wheel button in the bottom menu) and perform a Backup and Restore.

Tap on “Create Zip and Save” to generate a zip file with all your data, when the zip file is ready DMD² will ask you where you want to save it, we recommend sending it to Google Drive.

To restore use the “Import Zip and Restore”, it allows you to select your backup zip file to restore.

You can use this between different devices.

The only data which is not included is the offline map files, they are too big. For that reason you will always need to download the maps again.