Fresh install vs upgrade with migration of UmbrelOS1.0

Does anyone know what the migration step in the instructions for upgrading a Linux Umbrel node to 1.0 does? Is it just to move your installed apps back to the drive you install 1.0 on? If that is the case, then if an existing Umbrel node is on an external drive, can you install 1.0 on the internal drive and just point the new node to the apps on the external drive? Or is there something happening in the migration step to make the .54 apps compatible with 1.0?