This means that in the worst possible scenario, an update to the Address Book won’t become available to the user until 48 hours after the change.
This situation however is extremely rare since the default maintenance time on Exchange is at AM and updates and downloads are usually performed during working hours.
The final version is scheduled to be available in late 2015 and will probably ship at the same time as Exchange 2016. An Office 365 Group is represented as a group object in Azure Active Directory (AAD).
When a new group is created, a provisioning process kicks in to create a shared Exchange Online mailbox, which is used to store contributions to group conversations as well as a shared calendar.
The nickname list is generated automatically as you use Outlook.
Active directory has the correct info, and everything seems to be in place, our only issue is with the wrong name showing up in the shared Outlook calenders. I have frequently seen people change the CN (Common Name) of a user object, but not update the display Name attribute, or they do it the other way resulting in a user that is only half-way renamed.
However when other domain users use Outlook to connect to the user's shared calendar it still has the old username. When User3 connects to User2's shared calendar it still shows User1's name in the calendars list.
Coming from a Microsoft Active Directory (read as Microsoft Domain) environment I have seen cached exchange mode cause more issues then it "solves" and I generally recommend users turn it off.
Here are a few examples of issues that it can cause: That's enough for examples and time for a suggestion.