Microsoft has released Exchange Server 2016 RTM, available for download now. A public preview of Exchange Server 2016 has been available for customers to test and evaluate since July 2015.

Exchange Server 2016 represents Microsoft’s commitment to delivering an on-premises messaging product that “meet’s today’s business expectations.”

With the volume of email and other communications continuing to grow, people need tools that help them focus on what’s most important in their inboxes, schedules and interactions with others at work. And as the quantity of email data grows, so do the demands on IT to manage, preserve and protect it. To help you meet these challenges, we’ve deepened the integration between Exchange and other Office products, so your organization can be more productive and collaborate more effectively.

The key areas that Microsoft has focussed on with Exchange Server 2016 are:

  • Better collaboration – with Outlook 2016 and the new “Outlook on the web” (the new name for OWA) document sharing will be easier, replacing traditional email attachments with links to OneDrive for Business or SharePoint 2016 (currently in Preview).
  • Improved Outlook web experience – this is truly a big step forward for OWA (sorry, Outlook on the web) which I personally use about 50% of the time. The quick action “Archive” button is my favourite, as well as the pasting of in-line images. Emojis are nice as well I suppose.
  • Search – faster, more flexible, more intelligent. Search can always be better of course.
  • Extensibility – the add-in model for Outlook and Outlook on the web is in full swing. Interestingly the REST APIs have not made it into RTM, but we can likely expect to see those in a future update.
  • eDiscovery – an important addition is the ability to search, hold and export public folder content. Microsoft has moved through the five stages of grief over public folders and is now in the acceptance stage. Public folders, once considered deprecated, will be around for a long time and need the same compliance features as mailboxes.
  • Simplified architecture – combining Client Access and Mailbox services into a single server role greatly simplifies deployment and management. And the co-existence story for Exchange Server 2016 with Exchange 2013 and 2010 is set to make this one of the lowest friction upgrade paths in Exchange history.
  • High availability – many performance and stability improvements that have flowed down to the on-premises product from Microsoft ongoing experience running Exchange Online.

The new features are certainly interesting, but what about features that didn’t make the cut? A number of items that have been publicly discussed in Microsoft blog posts and sessions at Ignite are absent from Exchange 2016 RTM. Of course, all such information was subject to change before RTM. No doubt the primary driver here is to ensure features are fully developed and stable before shipping them in a future Cumulative Update for Exchange 2016.

A few of the missing features:

  • Search index from passive – the goal here is to have content indexes for passive database copies build/update from the passive database copy rather than replicate from the active database copy, which should reduce DAG replication traffic. No timeline on when this feature will appear.
  • Auto-expanding archives – the goal here is to have Exchange 2016 automatically provision additional archives for a user when their archive mailbox reaches 100Gb. This feature is still marked as “in development” on the Office 365 roadmap, so you should expect to wait at least until it is rolling out in Office 365 before it will appear in an on-premises CU.
  • Delayed lag playdown – lagged copy playdown will be enabled by default, causing lagged copies to automatically replay their log files and bring the database up to date if the DAG detects a loss of database redundancy, something that has reportedly avoided some potentially bad outage scenarios in Office 365. Delayed lag playdown will throttle that replay process based on the server workload, ensuring it does not overload the server.

It may be disheartening to see key features not make it into the RTM build. But on the other hand, most Exchange Server RTM builds are missing something that many of us would consider important. The quarterly update cycle (for now) with features shipping in Cumulative Updates should deliver these key features to us in the near future. But they have to be stable first.

Do you plan to deploy Exchange Server 2016? Let us know in the comments below.

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. Sandeep

    Hello Friends,

    I need MS Exchange Server 2016 Operating System ISO File download link.
    I need Core OS File.

    Kindly Help.

  2. Rangga

    Hi Paul,

    For Exchange 2016 evaluation license, is there any difference between licensed Exchange version?

  3. sagno

    je suis étudiant et j’étudie a Kofi Annan de guinée et je fait la licence 3 miage

  4. Jakob

    Hi Paul

    I’ve stopped a Exchange 2013 migration project after we’ve installed servers, and moved over CAS traffic from Load Balancer to Exchange 2013 successfully. But now we need to reuse hardware for Exchange 2016 – thus uninstalling Exchange 2013, going back to Exchange 2010 CAS (No mailboxes are moved).
    But customer is worried that since we’ve done forest, ad and schema prep for Exchange 2013 – but uninstall 2013 – that prep and installation of 2016 will fail. I’m not aware of any problems related to this, and had no problems reproducing this in my limited lab-environment. But this is 15000+ mailboxes so need to tread lightly —

    Do you have any thoughts on this ??

    regards; Jakob

    1. Avatar photo
      Paul Cunningham

      I doubt that will cause it to fail. If you want to be certain then you should set up the same scenario in a test environment.

      1. Jakob

        Great — thanks for getting back to me. It’s a bit difficult to try to replicate the same setup – given it’s a 2000 – 2007 – 2010 -partial2013 setup.

        Can have them setup a virtual 2013 not used for anything during migration, and decomission together with 2010 … better safe than sorry

        1. Jakob

          that is — they’ve migrated from 2000 via 2007 to 2010. Only 2010 + 2013 now 🙂

  5. Dave Valcourt

    Any timeline as to when we can expect to see the Exchange Sizing Calculator for Exchange 2016?

    1. Avatar photo
      Paul Cunningham

      I have no info on that. I think the 2013 calculator appeared about 6 months after 2013 RTM.

  6. Gordon Howes

    Aside from the improvements to Outlook On the Web, the release of Exchange 2016 does little to excite. DAG is proven and works very well but the lack of DAG Lag Playdown feature means there is not enough reasons to move to the product if you are already on the latest CU release of 2013. For me anyway 🙂

  7. jorg van impe


    I downloaded this morning exchange server 2016 RTM to install in a lab, afterwards i will do some migration path from exchange 2010 to 2016 and from 2013 to 2016.

    Best Regards

  8. Kannan

    We are planning to deploy a coexistence with Exchange 2010 and creating a new DAG to deploy 2016. Hope it won’t perform bad like EX2013 when we use more memory (256 GB) and 2 CPU with 24 cores.!!!!

  9. Milton Lopez

    Seems like yet another typical new Microsoft product to me: a few new features not fully developed yet, some missing ones, and lots of ultimately meaningless marketing. It took a number of CUs to make 2013 workable, so I’d expect 2016 RTM to be yet another quasi-Beta release.

  10. Alexandre Racine

    Honestly Paul, from a business perspective, except if you use OneDrive FB or SharePoint, which my clients don’t, there is nothing in there to make me upgrade from Ex2013. No public folders activesync contact/calendar sharing (on mobile phones), no intelligent spam fighter, in other words, this could have been Ex2013 SP1…

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