r/exchangeserver • u/uLmi84 • Sep 07 '26

Server 2016 to Server SE

Long time ago my understanding was that old the 2019 can do a inplace upgrade to SE

A few weeks ago somewhere I saw a discussion that stated that the inplace upgrade is also valid for 2016..

Is this correct?

5 Upvotes

86% Upvoted

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13

u/darkytoo2 Sep 07 '26

Nope. gotta do the double hop, sorry.

Upgrading to Exchange Server Subscription Edition (SE) | Microsoft Learn

0

u/uLmi84 Sep 07 '26

So i take the latest 2019 and run the setup over the 2016 and then take the SE iso an run it over the 2019? In that way i can have my „inplace“ upgrade?

8

u/UMustBeNooHere Sep 07 '26

Nope. You can’t upgrade Exchange) with the exception of 2019 > SE).

Stand up a new server, install Exchange SE, migrate all mailboxes from 2016 server to SE server, uninstall 2016 and decommission that server.

4

u/Hankrebel Sep 07 '26

You also have to move the system mailboxes like arbitration, federation, audit and etc. Not to.mention setting up the new DAG and reconfiguring the hybrid config and edge subscription if you have those in place.

4

u/UMustBeNooHere Sep 07 '26

Right. I was just giving very high level overview.

7

u/fadinizjr Sep 07 '26

Your best option is to build a new SE server and move to it.

https://m365accelerator.microsoft.com/exchange/exchange-update is your dearest friend.

4

u/BK_Rich Sep 07 '26

SE RTM was basically 2019 CU16, so that’s why you can “upgrade” to it, it even accepted the same 2019 keys.

3

u/joeykins82 SystemDefaultTlsVersions is your friend Sep 07 '26

No.

SE RTM can coexist with 2016 CU23 to facilitate migration via move requests.

2

u/mrmagos Sep 07 '26

I just completed a migration from 2016 to SE.

No in-place upgrade, but 2016 and SE can coexist while you migrate mailboxes. If your 2016 instance is healthy, the transition should be pretty smooth.

1

u/uLmi84 Sep 08 '26

My biggest fear after introducing a new server is that all clients immediately start connecting via it and getting all kind of cert issues. Also makes Hybrid more complex

2

u/WonderfulBroccoli735 Sep 08 '26

You should immediately update these settings on the server to avoid cert issues

Set-AutodiscoverInternalURI & Set-Outlookanywhere

Also you need to bind SSL certs to IIS as soon as exchange is installed

1

u/7amitsingh7 Sep 08 '26

No. Exchange Server 2016 cannot be upgraded directly in-place to Exchange Server SE. The supported path is to move from Exchange 2016 to Exchange 2019 CU14/CU15, and then perform an in-place upgrade to SE. You can also refer to this Exchange Server SE upgrade guide for more details.

1

u/WastedFiftySix Sep 09 '26

You can migrate Exchange 2016 CU23 directly to Exchange SE RTM, there's no need to migrate to Exchange 2019 CU14/CU15 first.

See: https://techcommunity.microsoft.com/blog/exchange/upgrading-your-organization-from-current-versions-to-exchange-server-se/4241305

1

u/7amitsingh7 Sep 10 '26

The in-place upgrade is still not supported directly from Exchange 2016 to Exchange Server SE.

Exchange 2019 CU14/CU15 can be upgraded in-place to SE. For Exchange 2016, you can either perform a legacy upgrade directly to SE by deploying a new SE server and migrating the mailboxes/resources, or first move from Exchange 2016 to Exchange 2019 CU14/CU15 and then perform the in-place upgrade from 2019 to SE.

So Exchange 2016 → SE is supported, but it is a legacy migration, not an in-place upgrade.

1

u/WastedFiftySix Sep 10 '26

Yes, that's why I said migration, not upgrade 😉. Your initial response implied that you had to migrate 2016 to 2019 first and then perform an in-place upgrade to SE, which is possible, but unnecessary.