Microsoft has announced the latest quarterly updated for Exchange Server 2016 and 2013.

For Exchange Server 2016 this release includes the following improvements for on-premises customers:

Those changes do not apply to Exchange Server 2013. From Microsoft’s blog post:

These features are targeted to Exchange Server 2016 only and will not be included in Exchange Server 2013. Exchange Server 2013 already has its own implementation of Sent Items Behavior Control which is different than the version we are releasing today. The Cumulative Update 6 behavior is more closely aligned with how this worked in Exchange Server 2010. Due to architectural differences, the configuration of this feature is not retained if mailboxes are moved between Exchange Server 2010 and Exchange Server 2016 or between Exchange Server 2013 and Exchange Server 2016.

Microsoft also shared progress on two other matters:

  • Support for TLS 1.2 is described as “improved”, but Microsoft is not ready to recommend deprecating TLS 1.0 and 1.1 yet.
  • .NET 4.7 compatibility testing is progressing well with no issues found so far, but they are not ready yet to declare .NET 4.7 supported for Exchange servers.


About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for


  1. George Schneider

    Is anyone aware of a reported issue after updating to Exchange CU6 and an issue with disabling and enabling existing transport rules. I’m seeing the following in both ECP and EMS.

    Software\Microsoft\MSIPC\CurrentVersion not found

    The work around I’ve been using is to delete and recreate any rules that need to be disabled and later enabled.

    The following two links seem to suggest this could be a potential bug in CU6

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