We have been successful in the restoration of another mailbox database that is used by 1 of the 4 affected email servers.
Mailboxes are continually being restored throughout the rest of today with an estimated completion by later this afternoon/evening.
Some users will find that their access to email may return sooner then others which is simply due to the restore process.
Also note that email via mobile devices will be affected for some users during this time.
At the moment 77% of all user mailboxes are accessible.