How do I move my mailboxes to the new Email menu?

For now, you will need to contact support to request the migration of your mailboxes to the new menu.

This will not cause any service interruption. 

All settings will remain the same (capacity, plan, auto-renewal)

Please note:  the migration is done by domain. You can therefore request the migration of all mailboxes for a domain to this new app.

You can test it.
If it works for you, you can then request the migration of the other domains.

In the near future, you'll be able to perform migrations yourself from your domain app