What’s New and Cool in Exchange 2016 – It’s out now!

10/12 Update: Link to Exchange 2016 Preferred Architecture added
10/2 Update: Known Issues section added near the end

Continuing my “What’s New and Cool” series that started with Exchange 2007, this article is on Exchange 2016 which was released today! For the latest timeframe information on the other Wave 16 releases see this roadmap page by Redmond Magazine.

Download here | EHLO Blog Post | Release Notes

Exchange 2016 builds upon Exchange 2013 and the extensive experience Microsoft has gained from running Exchange in the cloud publicly since the Business Productivity Online Suite (BPOS) in November 2008 and Office 365. The experience Microsoft has gained from running Exchange 2016 in Office 365 for almost a year will benefit on-premises customers greatly. The same code using for Office 365 is converted into on-premises installable version, which a few features disabled that are only available in O365. Sadly Clutter and the new “Office 365” groups will be only available in O365. For info on these two technologies see these two articles by Tony Redmond: Q&A Clutter and Using Office 365 groups with Outlook 2016. You can read more about Office 2016 here What’s New and Improved in Office 2106 & Office 2016 Quick Start Guides.

While I still love Exchange and recommend it over any other on-premises email and calendaring solution, for small, medium, and even large organization, the value that Office 365 provides is huge! If you’re running Exchange on-premises today and are a small (<250 users) organization there are VERY few reasons to be running your own messaging systems anymore. Medium and larger orgs tend to have some special requirements and a migration to O365 does take proper planning and testing, so the move isn’t as quick or easy but it still a very viable option for most orgs. Check out this Microsoft site for information on this topic: http://www.whymicrosoft.com/see-why/customers-find-value-choosing-office-365/

2016 Announcements and Articles

Here are some of the best places to go for more details on Exchange 2016:

Also join the Exchange Information Sharing Facebook group here that I admin with Tony Redmond and a few other Exchange MVPs: https://www.facebook.com/groups/MSExchangeInfo/. This group is primarily focused on Exchange 2016.

Key Changes in Exchange 2016

  1. One Role to Rule Them All – Single role only, unless you count the Edge Transport server
  2. Reliability and performance improvement – This is major benefit of “Born in the cloud”, 2016 being designed for and tested in O365 for almost a year before going to public beta
  3. Faster and more intuitive search
    1. Server side search speed significantly improved
    2. Message index by the Transport layer – No delay on messages and attachments showing up in search results
    3. Outlook 2016 will utilize server side search improvements, even when in cached mode,
    4. Fuzzy logic based search and suggestions shown as you type; based on content in your mailbox, people you communicate with, and your query history
  4. 33% faster failovers than 2013
  5. Simplified document sharing with support for OneDrive and SharePoint 2016
  6. New Outlook web experience

General Changes

Reliability, Scalability & Performance

  1. Additional storage performance improvements – 22% less IOPS than 2013 or 95% less than 2003! – STOP using expensive SAN solutions and high speed disks for Exchange!!!
  2. Faster and more scalable eDiscovery – Big effort was spent on improving search performance in 2016
  3. Hybrid improvements – Improved UI & error handling
  4. Database divergence detection and repair
  5. Support for 1 million Public Folders, also supported in 2013 CU8
  6. Resilient File System (ReFS) recommended for DB & log volumes
  7. Refactoring of mailbox size statics to be more accurate, expect around a 10% growth in reported usages of mailbox
  8. Support for dynamically expanding VHDX files – Legacy expanding VHD and differencing disk are still unsupported

Server and Role Changes

  1. “Up-Down” proxy support for Exchange 2013 – 2013 and 2016 can proxy to other 2013 or 2016 servers
  2. Office Web Apps Server required for Office document viewing in OWA/OotW
  3. Non-IP/Administrative Access Point (AAP) DAG used by default

Enhanced Features, Extensibility & Usability

  1. Modern attachment support – With Outlook 2016 and OotW using file sharing services, like OneDrive, will be much easier
  2. DLP improvements – More templates, Mail Tips, and document fingerprinting
  3. MAPI over HTTP on by default – Added in Exchange 2013 SP1, but could only be enabled at org level; with 2016 it can be enabled at the user level
  4. Support for litigation hold of Public Folder content
  5. Supported in Azure, using premium storage only – But this should only be an option in very special cases, if you want hosted Exchange use Office 365
  6. Greater extensibility – Greatly improved Add-In module for Outlook and Outlook on the Web

OWA Changes

  • Renamed to Outlook on the Web
  • GAL UI picker removed, replaced with search paradigm
  • UI being tweaked to look more like “Outlook Mobile”
  • Frequent contacts tracked and suggested when starting a new email
  • Undo action button, like accidental deletes & moves
  • Pinning of message to top of the Inbox
  • Sweep support for touch devices
  • Improved, “Modern Attachment” attachment support, including Most Recently Used (MRU) list of attachments

New APIs

Preferred Architecture for 2016

See The Exchange 2016 Preferred Architecture post on the EHLO blog for full details. Lots of great info in this Channel 9 – Microsoft Ignite session by Ross Smith also: Exchange Server Preferred Architecture, but in summary:


  • Multi-role (it’s your only option with 2016 now)
  • Commodity hardware
    • Dual-socket system, 20-24 cores max, and mid-range processors
    • Max of 96GB of RAM


  • Large capacity 7.2k SAS disks
  • Battery-backed cache controller (75/25)
  • Multiple databases per volume
  • Auto-Reseed with hot spare drives
  • Data volumes are formatted with ReFS and encrypted with BitLocker


  • Single namespace (FQDN) used for all sites
    • Except for Outlook Web Apps Server, should be on namespace per datacenter for OWAS
  • Layer 7 network load balancer with one VIP per datacenter, with per-service health checking.
    • No session affinity
      • Except for Outlook Web Apps Server, should be enabled for OWAS
    • Round-robin Geo-DNS
    • Symmetrical DAGs spanning datacenters
    • No administrative access point
    • Single network for replication and client traffic
    • Utilize a third datacenter or Azure for Witness server placement, if possible
    • Deploy four copies per database, two copies in each datacenter
      • One copy is a lagged for seven days

Known Issues

  1. 10/1: Can add an Exchange 2013 database to a 2016 DAG
  2. 10/1: Can’t connect to archive mailbox when using MAPI over HTTP
    • Only an issue if 1) MAPI over HTTP is enabled on the user’s mailbox AND 2) MAPI over HTTP is disabled at the organization level
    • Users will get the error: “The set of folders cannot be opened. The attempt to log on to Microsoft Exchange has failed”
    • Workaround: Disable MAPI over HTTP for the mailbox
      • Set-CasMailbox -MapiHttpEnabled $False

Features that didn’t make RTM but should appear in a future CU

  1. Auto-expanding archives – Providing nearly unlimited archive mailboxes, if enabled & desired
  2. 40% reduction in network usage – Indexing built using local DB copy instead of active copy only
  3. Loose Log Truncation aka Log Reply Manager enabled by default – Prevents an off-line database from causing excessive and space consuming log build up on other replicas

Discontinued from 2013

  1. Client Access and separate Mailbox roles, just Exchange Server now
  2. Exchange 2007 & Outlook 2007 support
  3. Windows Server 2008 R2 and earlier support for Exchange servers
    1. Must be at least one Windows 2008 R2 or higher writable DC\GC in each AD site with an Exchange 2016 server
    2. Windows 10/2016 Server may or may not be supported with Exchange 2016 RTM
  4. Pre-Windows Server 2008 forest or domain functionality level
  5. MAPI/CDO – REST APIs should be used
  6. Outlook 2008 EWS for Mac

What’s discontinued in Exchange 2016, include a list of features disconnected from 2010 also see: https://technet.microsoft.com/en-us/library/jj619283(v=exchg.160).aspx

De-emphasized, may not be in the next version

  1. Third-party replication APIs
  2. RPC over HTTP
  3. DAG support for cluster administrative points

What’s New and Cool Historical Posts

2013: https://blog.jasonsherry.net/2012/07/31/new_cool_exchange_2013/
2010: https://blog.jasonsherry.net/2009/04/15/whats-new-and-cool-in-exchange-2010-e14/
2007: https://blog.jasonsherry.net/2006/07/21/whats-new-exchange-2007/

About Jason Sherry

I am a ~30 year Exchange consultant and expert. I currently work for Commvault as a Solutions Specialist for Microsoft Infrastructure For more info see my resume at: http://resume.jasonsherry.org
This entry was posted in Exchange, Technical and tagged , , . Bookmark the permalink.

3 Responses to What’s New and Cool in Exchange 2016 – It’s out now!

  1. Pingback: What’s New and Cool in Exchange 2013 | Jason (Izzy) Sherry's Blog

  2. Manuel says:

    ¡Great post! If someone wants to try it: Step by step installation of Exchange Server 2016 RTM: http://www.sysadmit.com/2015/10/exchange-server-2016-instalacion.html


  3. Pingback: Exchange 2016 is here! - SuperTekBoy

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