Exchange 2013 CU6: Don’t deploy in Exchange 2007 mixed mode and Hybrid
Microsoft recently released Exchange 2013 CU6 which is fixing a lot of issues which were coming in CU5. My Lab installation on new server went very smooth.
Exchange 2007 Mixed Mode issue
While I tested DAG, mailflow and run other test, people reported the issue with the Exchange 2007 mixed mode.
In Exchange 2007 mixed mode, the issue reported as an issue with databases flapping which was due to exchange 2007 mailboxes are talking to exchange 2013 mailboxes.
We reported the issue to Microsoft and Microsoft confirms that there is an issue which happens when exchange 2007 server user attempts to access a delegated mailbox that is on exchange 2013 server.
Microsoft is tracking the issue by KB2997209 which is still being published.
Meanwhile Microsoft MVP Jeff Guillet also reported another issue in Hybrid environment. To know more about this issue. Please have a look here.
Microsoft decided to continue working on this issue even over the Labor Day weekend.
We expect that Microsoft will fix these issues in CU7. In the meantime, we recommend exchange 2007 mixed mode and hybrid customers do not deploy CU6 at this time and wait for Microsoft’s update.
Update at 5:00 PM – Microsoft has released the update. Here is the link. Ryan has tested it and it has fixed the issue.
Microsoft Solutions Architect | Exchange Server