The migration from v1 to v2 is fully automated. Just install the new module version and follow the process in the UI that guides you step by step.
To not leave you in any broken state or leave editors unable to update content, you can still use your v1 Sync Core while the migration is running. So even if anything would go wrong, your update process can still continue. You can even test individual updates with v2 while v1 is still used for all regular updates to ensure a smooth transition.
For on-premise users
The Sync Core must be accessible directly by end-users.
Mongo v4.4+ is required now instead of 3.6+.