Provisional Group Bookings - Mark all reservation items (rooms) of a reservation as provisional. Also, If you have the optional extra for auto-release, the reservation items will be automatically cancelled.
Auto Dirty Rooms - When checking out a reservation item you can set your diary to automatically mark that room as dirty. You can make this setting change under Settings -> Customise Diary.
Dirty Rooms on Housekeeping - The Housekeeping report got some love this release with a nicer design and a new Dirty Rooms section.
Edit one reservation item of a group booking - If the reservation contains 3 or more reservation items (rooms), you will be asked if you want to edit all items or just the one you clicked on.