A 2.7.1 release with significant performance – mostly for AdminUI – was just released. Go to Downloads to see the a more detailed changelog.
The main focus was on major improvements in times needed to load list of users and groups tree in AdminUI (significant if you have thousands of users/groups or just a slow DB). There is also a performance bugfix for admins who were members of many groups (100+): using AdminUI by such users is not extremely slow anymore, there is no difference on amount of group memberships.
Additional improvements include enhanced message templates loading: Unity can be configured to sync configured templates on startup and AdminUI allows to reload templates from configuration at runtime. There are also several other minor enhancements.