Exchange Server 2016 is available! Now what?

Exchange logo (2013+) in blue, with the text Exchange after it (also blue) Reading Time: 3 minutes

Today Exchange Server 2016 for on-premises installations became available!

Some important links:

Before you rush with installing it, beware of the requirements:

  • Coexistence only with Exchange 2010 SP3 RU11 and/or Exchange 2013 CU10
    • No Exchange 2007 coexistence support!
  • Install OS can be Windows Server 2012 or 2012 R2 Standard or Datacenter
    • Windows Server 2016 support may require a Cumulative Update
  • Windows Server 2008 Forest/Domain Functional level
    • Previously a Functional level of  2008 R2 was announced
  • Outlook 2010, 2013 and 2016 and Outlook for Mac 2011/for Office 365
    • Some updates are required
    • Outlook 2007 is not supported

If your environment doesn't support these requirements, you have some work to do. Regarding any coexistence issues, work you way to Exchange 2013 then to 2016. The migration from 2013 to 2016 is the easiest and risk free transition to date. Some information can be found in the Ignite session "Deploying Exchange Server 2016" by Brian Day. Remember, once you've updated your AD Schema you will not be able to add new legacy Exchange version servers other than 2016.

Other interesting Exchange 2016 sessions from Ignite are:

Do note that some requirements might have changed after those sessions (which they themselves warn for).

Please note that some functionality isn't available yet, for instance SharePoint 2016 is currently only in preview and it's not recommended to install that in your production environment. For viewing/editing Office documents in Outlook on the web (Ootw, the re-branded Outlook Web App or OWA), you will require the Office Online Server which is currently also in preview and not supported in production environments. Until it's general available Ootw users will have to download Office documents and view them locally.

Other functionality that had been announced and aren't available in this build will be become available in upcoming Cumulative Updates, the first one in early 2016. Most notable now missing but upcoming features IMHO are Search Index from Passive DB, REST API's, Auto-Expanding archives and Inline image controls for Outlook on the web.

Currently no sizing information has been released, such as an Exchange Server Role Requirements Calculator specifically for Exchange 2016. Although Exchange 2016 might feel more like Exchange 2013 Service Pack 2, I wouldn't blindly use the Exchange 2013 calculators for 2016. For instance: the required IOPS per mailbox has decreased again. That probably has some trade off in memory as it had in Exchange 2013. Also, the Search Index from Passive DB will have an important impact on the WAN requirements if you plan to have a stretched DAG (over two physical sites), but is currently not in the RTM build. However, it's something an upcoming calculator will most likely incorporate in order to present you correct WAN usage with this feature (and thus might save you money by preventing extra investments in WAN bandwidth).

So, if your environment has all the necessary requirements ticked off, should you transition immediately? Although my experience with earlier build has been okay (already better than Exchange 2013 RTM was, but the current 2016 experience is from working in a lab environment, mind you), it's probably best to wait until some of the sizing tools become available or your specific UM Language files, if required. You can get a lot of issues when the servers aren't sized properly, best to have some patience and get it right.

However, there is no reason to prepare yourself if you want to prepare for an eventual migration. You can test this build out including the SharePoint and Office Online Server preview in an isolated lab environment and get a feel how it works and test you dependencies with other products (like back-up, anti-virus etc.).

If you really can't wait for some of the nifty new features in Exchange 2016, maybe you should consider Office 365 as some of them are already implemented. But what's the fun in that 😉

Note: At this time you can mix 2013 and 2016 servers in a single DAG. THIS IS NOT SUPPORTED AND SHOULD NOT BE PERFORMED. It will be blocked in an upcoming update. This is stated in the release notes and Michel de Rooij and Paul Cunningham have blogged about this as well.

/edit: Added UM pack link. Added warning about mixing Exchange builds in one DAG



    Perhaps a typo on the" Requirements Section" , IMHO the minimum Fonctional Level for E2013 was W2003 r2 and not "W2008 R2"

    Have a nice day

    • Dave Stork

      For 2013 it was 2003 Native (SP2 required), however I meant to say that previously for Exchange 2016 a functional level of W2008 R2 was announced. So they lowered that requirement. I will make it somewhat more clear, thank you!

  • Christian Beauregard


    Do you know if they added automapping feature through security groups which is lacking unless you script it?

    • Dave Stork

      I haven't tested it but I assume that there has been no change in that department.

      To understand, the MsExchangeDelegateLink attribute of the user who receives Full Access permissions is changed to include the mailbox ID to which you have Full Access & AutoMapping. This is read by Outlook via AutoDiscover and that triggers Automapping. So it's information in your own account, not the shared mailbox. That why it doesn't work with groups, for that to work a mechanism that checks memberships and adds that attribute to accounts who are members must be in place. Could get kinda tricky.


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.