Does outlook exchange online support MAPI over HTTP2?

Question

Does outlook exchange online support MAPI over HTTP2?

Avinash Ranjan 1

I am trying to explore if MAPI can work with HTTP/2. And since HTTP is just a transport wrapper on top of MAPI, I believe it should have no problem working with HTTP/2 as well.

While checking the exchange online(outlook.office365.com) I found that it is still using HTTP1.1 even though the server is Microsoft-IIS/10.0 which supports HTTP/2.

Now I want to understand if MAPI over HTTP2 is possible? If yes, why is it not enabled for outlook.office365.com?

JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-22T02:58:19.397+00:00

Hi @Avinash Ranjan ,

Welcome to Q&A!

I tried a lot of research about the MAPI over HTTP2 you mentioned above, searching different kinds of documents and blogs, but sorry I could not find any available evidence which tells the MAPI over HTTP2 is able to be supported.

If you do still would like this feature, I would suggest you to submit your request via Outlook 365 > File > Feedback > Suggest a Feature like below. Microsoft may notice it and add it in the later version.

Thanks for your understanding and support.
JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-23T08:09:56.33+00:00

Hi @Avinash Ranjan ,
Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.
Avinash Ranjan 1 Reputation point

2021-07-23T08:23:29.207+00:00

Hi @JeffYang-MSFT
I have submitted a request for the same. Meanwhile I will try setting up an Exchange server to see if I can make MAPI over HTTP/2 work.
JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-23T09:58:44.78+00:00

Hi @Avinash Ranjan ,
Thanks for your reply and sharing.
If you have any update about this, please feel free to post back and discuss with us here.

1 answer

Your answer

JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-22T02:58:19.397+00:00

Hi @Avinash Ranjan ,

Welcome to Q&A!

I tried a lot of research about the MAPI over HTTP2 you mentioned above, searching different kinds of documents and blogs, but sorry I could not find any available evidence which tells the MAPI over HTTP2 is able to be supported.

If you do still would like this feature, I would suggest you to submit your request via Outlook 365 > File > Feedback > Suggest a Feature like below. Microsoft may notice it and add it in the later version.

Thanks for your understanding and support.
JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-23T08:09:56.33+00:00

Hi @Avinash Ranjan ,
Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.
Avinash Ranjan 1 Reputation point

2021-07-23T08:23:29.207+00:00

Hi @JeffYang-MSFT
I have submitted a request for the same. Meanwhile I will try setting up an Exchange server to see if I can make MAPI over HTTP/2 work.
JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-23T09:58:44.78+00:00

Hi @Avinash Ranjan ,
Thanks for your reply and sharing.
If you have any update about this, please feel free to post back and discuss with us here.

Answer 1

Avinash Ranjan 1

@JeffYang-MSFT I have been trying MAPI over HTTP2 with latest exchange server 2019 and IIS 10.

HTTP2 is enabled on my IIS 10 server.

There are several virtual directory mapped on my exchange server(see below).

While I am able to get HTTP2 connection for some of the virtual directories(ecp, owa - these two I have tried) for others it is still HTTP 1.1 and '/mapi' is one of them.

Even though this time I am certain that I have enabled HTTP2 for IIS server MAPI connections still uses HTTP1.1.

I am wondering now if MAPI over HTTP2 has been disabled intentionally.!! If yes, why!!

JeffYang-MSFT 6,261 Reputation points Moderator

2021-07-29T02:19:39.68+00:00

Hi @Avinash Ranjan ,

Thanks for your reply and sharing.

I did searched a lot about MAPI over HTTP2 in the past few days, documents, blogs and some others, but failed to find any information which could explain that. Considering that you have already post your feed back, let's wait and see if Microsoft could support this feature in future updates.

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Does outlook exchange online support MAPI over HTTP2?

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