Announcing Exchange ActiveSync version 16.1

We are excited to announce enhancements to Exchange ActiveSync (EAS) in Office 365 and a future cumulative update to Exchange Server 2016 that will soon be available to Exchange ActiveSync clients.

We are introducing version 16.1 of the EAS protocol, which contains three new major capabilities:

  1. Improved Keyword Search - Get quicker, more relevant results when searching your inbox. Clients can now perform Keyword Query Language searches (from, to, subject, etc.) by using the new Find command.
  2. Propose New Time - Users have asked for the ability to propose a new time for a meeting while on the go, and we have added full support for new time proposals in EAS 16.1.
  3. Account-Only Remote Wipe - Administrators can now request clients using EAS 16.1 to wipe only Exchange data from a user's device.

While not a part of EAS 16.1, we also want to note that both Office 365 and customers can now utilize the OAuth 2.0 protocol for authorization through EAS.

Customers with their mailbox in Office 365 can take advantage of these new features when their favorite EAS client is updated.

Update: We are happy to share that iOS 10, announced June 13th at Apple’s Worldwide Developer Conference, plans to support the above features of EAS 16.1 when it releases in the fall. Apple has also announced support in the same release for draft email syncing, which was introduced in EAS 16.0, the OAuth 2.0 protocol for authorization of accounts and support for forwarding meeting items.

As an end user, how can you tell if your mailbox is enabled for EAS version 16.1? The simplest way is to run an "Exchange ActiveSync" test at and look for version 16.1 listed as one of the supported protocol versions (MS-ASProtocolVersions header in the OPTIONS command response) in the test results. Note that you need a valid Office 365 email address and password in order to run that test, and the results are specific to that mailbox only (not the entire tenant).

For partners who are building Exchange ActiveSync applications, preview documentation for EAS v16.1 is now available at

Comments (11)
  1. i don’t se it working on my iOS mail client.

    1. Hi @Exchangeitpro,

      Please note the update to the post that we have added today. iOS 10 will include the specific features as detailed when it is released this fall.


      1. Ok thanks, here is the blog about it. Also it workd with Outlook App not the Other OWA APP, see my blog for details.

        1. Qaas says:

          @ExchangeITPro (Adnan) – The OWA App for iOS uses the same code as OWA uses when you use it within any browser on a device, it is not using EAS protocol for the ‘propose new time’ feature like you have mentioned in your blog.

  2. Someone says:

    Why does for consumer accounts return MS-ASProtocolVersions: 2.5,14.0? Consumers will not get any benefit from any improvements in the past few years or with iOS 10. The same server for an Office 365 E3 account returns MS-ASProtocolVersions: 2.0,2.1,2.5,12.0,12.1,14.0,14.1,16.0,16.1. Please support the same EAS versions for consume accounts as for Office 365 business accounts or at least 2.5,14.0,14.1,16.0, and 16.1.

  3. pilo says:

    Any documentation of how to do this… ?
    “both Office 365 and customers can now utilize the OAuth 2.0 protocol for authorization through EAS.” ??

  4. HS says:

    Hi Tyler, is this true that with Exchange (online) ActiveSync 16.1 admins can use the [-AccountOnly] switch with Clear-MobileDevice PowerShell command to ‘only’ remote wipe out the Exchange account and data from mobile device? if this is true it means admins can isolate the wipe out and leave the mobile device data intact.

  5. What CU will EAS 16.1 be included in for 2016? I just installed Exchange 2016 CU4 but it does not seem to be there as testconnectivity only shows 16.0 being presented.

  6. Luuk Dost says:

    I cannot find any information of when Microsoft will release this for Exchange 2016 and it’s been more than a year ago now that this article was being published.

  7. Luuk Dost says:

    Does anyone know when this will be released for Exchange 2016? This is article is from one year ago, but I cannot find any information of it. We could really use it in our company.

    1. Luuk Dost did you ever get an answer? I’m running Exchange 2016 with lacking only the last CU’s. CU7, 8 and 9. I cannot see in any CU if EAS 16.1 is part of the update.

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