"This vault needs to be migrated to a newer version" - how do I do this?

Opening the desktop app in Windows 10 it says:

"Vault version upgrade

_This vault needs to be migrated to a newer format. _
Please make sure synchronization has finished before proceeding"

So how do I migrate the vault to a newer format - what do I need to do?

How do I know when synchronization has finished?

Any help would be greatly appreciated, thanks

when your sync app (eg DropBox, GDrive, Onedrive, etc) has finished. You can check the icon in the task-bar. It usually shows if the app is still syncing, or if the app does nothing.

As far as I know the migration is done by cryptomator automatically as soon as you confirm to continue the process.