And so it begins. Few moments ago, the Exchange team published the public preview of Exchange 2016. The build number of the preview version is 15.1.225.17 (yes, 15.1.*, not 16.*). Exchange 2016 Preview raises schema to version 15317.

The team’s post contains information on the changes and features introduced in Exchange 2016. Many of these were already announced at Ignite earlier this year. An earlier blog post on these announcements can be found here.

With this Exchange 2016 Preview, there are important deviations from announcements made at Ignite 2015:

• Minimum required Forest Functional Level (FFL) and Domain Functional Level (DFL) is Windows Server 2008. At Ignite is was announced Windows Server 2008 R2 FFL/DFL would be required.
• Supported Operating Systems will be Windows Server 2012 and Windows Server 2012 R2. At Ignite, it was announced Windows Server 2012 was not going to be supported. Note that Windows Server 10 (Windows Server 2016) is currently in preview, is not (yet) supported, but likely will be at or shortly after both reach RTM status.
• Coexistence requires  Exchange Server 2013 Cumulative Update 8 or Exchange Server 2010 Service Pack 3 Rollup 9. This is lower than Exchange 2013 CU10+ or Exchange 2010 SP3 RU11+ as was mentioned at Ignite.
• Exchange 2016 Preview works with Outlook 2013, Outlook 2010 with KB2965295, or Outlook 2016 (currently in Preview). This is a lower requirement than Outlook 2010 SP2 with KB2956191 and KB2965295 or Outlook 2013 SP1 with KB3020812 as announced at Ignite. Note that Mac users can utilize Outlook for Mac for Office 365 or Outlook for Mac 2011.
• Not mentioned at Ignite, but something which recently was introduced in Exchange Online, is the introduction of auto-expanding In-Place Archives in Exchange 2016 Preview. After filling up the initial archive with 100 GB (default quota), Exchange will create auxiliary archives in chunks of 50 GB. To the end user using Outlook 2016 or Outlook for the web (the new Outlook WebApp branding), these archives will appear as a single archive. Downlevel Outlook clients will only display the initial 100 GB archive.

Meanwhile, the TechNet technical library has been updated with information on Exchange 2016. Be advised that this documentation may be incomplete and subject to change, and in fact may even be not on par with the preview product. However, as the product reaches RTM, the documentation should become more complete and final.

Some links to get you started:

• The official announcement from the Exchange Team can be found here
• Preliminary documentation for Exchange 2016 can be found on TechNet here
• Documentation on Active Directory schema changes for Exchange 2016 can be found here

Needless to say, this is a preview. It’s great to play with in a lab, but don’t install it in your production environment unless you are part of the TAP program.

You can download the Exchange 2016 Preview here