iOS 11 and Windows 2016 Compatibility Issue
Announcement made by Derek Curtis - September 14, 2017 at 10:20 AM
Locked Employee Post
[UPDATE: With the release of iOS 11.0.1, the compatibility issue has been resolved.]
 
All,
 
We sent the following email to all SmarterMail customers last night, but I also wanted to post the info here, just in case. Please review and let us know if you have any questions...
 

Apple has announced that iOS 11 will be released to the public on Tuesday, September 19th.

Normally, this is a wonderful occasion because companies such as Apple provide fixes and features that make our lives better! Unfortunatly, iOS 11 is going to introduce issues for a lot of customers running Windows Server 2016.

We have been testing the BETA releases of iOS 11 for a couple of months and are working with Microsoft and Apple to resolve the issue but, unfortunately, the issue still exists with the Golden Master (GM) release of iOS 11.

The overview of the issue is that Exchange ActiveSync (EAS) users will not be able to REPLY to, or FORWARD, messages with attachments from the default Mail app on iOS 11. Please understand that this is NOT a SmarterMail issue but an iOS 11 and Windows Server 2016 compatibility issue that affects ALL versions of SmarterMail as well as other mail servers and services, including Microsoft Exchange Server customers using Windows Server 2016.

If you are using Windows Server 2016, please read further for a more detailed explanation and workaround:

The cause of the issue is related to the implementation of HTTP/2 in either Windows Server 2016 or in iOS 11. HTTP/2 is a major revision of the HTTP network protocol used for communication across the internet. Windows Server 2016 and Windows 10 both implement, and default to, HTTP/2 versus the more legacy HTTP/1.1. With iOS 11, Apple is now using HTTP/2 because Windows Server 2016 supports it.

If your mail server is running and older version of Windows Server, you will not see this problem as iOS 11 will continue to use HTTP/1.1.

As a workaround, system administrators can modify the Windows Server 2016 registry to “act as” previous versions of Windows Server, essentially telling iOS 11 to use the HTTP/1.1 protocol. The following keys would need to be modified AND the server rebooted:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters
EnableHTTP2Tls REG_DWORD 0 — the default is 1
EnableHttp2Cleartext REG_DWORD 0 — again, the default is 1

Again, this is ONLY necessary if your mail server is running Windows Server 2016. NOTE: Editing the registry should be handled by someone with experience. If you aren’t comfortable with making registry changes , open a ticket with our support team.

We are going to continue reaching out to Microsoft and Apple to help them resolve the issue. We will update our customers when we have more information.

We hope this information helps you continue to provide seamless mail services for your customers.

Derek Curtis
COO
SmarterTools Inc.
(877) 357-6278

8 Replies

Reply to Thread
0
Thanks for sharing. That's an intersting issue. Looking forword to seeing who is going to really fix this.
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Thomas Stensitzki
MCSM Messaging, MCM: Exchange Server 2010
https://www.granikos.eu
0
Those keys don't exist in the registry. I created them and just want to be sure if this is correct? See attached screenshot:
 
0
You'll wanna make sure those values are 0, since we are trying to disable these features.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
Done.
0
Chris - Make sure you also reboot as well.

Christopher

1
Just to follow up on this, the issue is now "official": 
 
 
Here's the Apple support doc: https://support.apple.com/en-us/HT208136
Derek Curtis
COO
SmarterTools Inc.
(877) 357-6278
0
Yes, did that. So far no complaints so far.
1
A final update to this thread: With yesterday's release of iOS 11.0.1, the compatibility issue has been resolved. Apple Mail now recognizes HTTP/2.
 
We've removed the "fix" and quadruple tested and we can confirm that the new update to iOS 11 DOES, in fact, solve the problem. Therefore, if you have the "fix" in place, you should be okay if you remove it.
Derek Curtis
COO
SmarterTools Inc.
(877) 357-6278