Organizations Need to Prepare Now to Move to Exchange Server SE in 2025

This fine site holds many articles about Exchange Server. Our thoughts therefore focused on the recent communication from the Exchange development team laying out their plans and recommendations for the transition to Exchange Server subscription edition (SE). There are many mentions of Exchange 2019 in the text, but the essence of the message is that those running on-premises Exchange servers need to figure out their plan to upgrade their organization to run Exchange Server subscription edition after its release in summer 2025.

Licensing for Exchange Server SE follows along the same lines as Exchange 2019. Users must have an Exchange Online license or a Client Access License (CAL) purchases through Software Assurance. Free licenses will be available for Exchange Server SE hybrid servers. It will also continue to be possible to manage Exchange recipient properties on-premises with PowerShell or using the Exchange Management tools without the need for a server.

The Next Three Exchange Server Releases

Microsoft’s next three releases of Exchange Server are Exchange 2019 CU15, Exchange Server SE, and Exchange Server SE CU1. The first release of Exchange Server SE is essentially a rebrand of Exchange 2019 CU15 with a few tweaks such as the removal of the Outlook Anywhere protocol. Its sole purpose is to establish the beachhead for the subscription edition.

These releases will appear starting in the second half of 2024 with Exchange 2019 CU15. No further updates will appear for Exchange 2016 and Exchange 2019. Critically, none of these releases support coexistence with Exchange 2013, and when Exchange Server SE CU1 appears in late 2025, coexistence with all previous on-premises versions of Exchange Server disappears.

In other words, organizations who intend to remain with an on-premises email service should be on Exchange 2016 CU23 now to be ready to move to Exchange 2019 CU15 when it appears. It’s a pain to upgrade Exchange organizations but you should be running a supported version of Exchange 2016 and need to get to Exchange 2019 to make the jump to Exchange Server SE. The need to upgrade is valid for hybrid organizations and edge servers too.

Interestingly, Exchange Server SE does not periodically check with the mother ship that it is correctly licensed. The installation procedure performs a license check and if that passes, you’re good to go until the time comes to update the server. To stay in compliance with licensing requirements, users need Exchange Online licenses or CALs.

Organizations will need to apply server updates on a more consistent basis than has been allowed heretofore. The whole point about a subscription edition is that you subscribe to keep the server updated with new functionality, bug fixes, and security patches. Acknowledging that Exchange server upgrades can be painful, Microsoft will introduce a new server upgrade process that’s similar to installing a cumulative update. In other words, server upgrades should be faster and easier to perform, so there’s no excuse for not upgrading.

Transport Blocking Will Affect Exchange 2016 and Exchange 2019

Microsoft will encourage the transition by using the transport enforcement system to block email traffic from Exchange 2016 and Exchange 2019 servers to Exchange Online after those servers become unsupported and Exchange Server SE is available.

As I understand it, the view from Redmond is that the tactic of blocking old Exchange servers from being able to send email to Exchange Online is very successful and has changed the way customers think about server upgrades. You might or might not agree, but blocking email from obsolete servers is certainly an effective way to remind a company that running old email software is not good in a world where cyber criminals delight in compromising unpatched servers.

A New World

It’s clear that the old way of running a mixture of servers installed with different versions of Exchange Server will soon disappear. Network-based threats mandate that software must be kept updated. Exchange Server is no different from any other critical piece of your IT infrastructure. It just happens to have a poor reputation gained in episodes like the HAFINUM attack because of a lack of discipline and rigor around server upgrades.

Far fewer organizations run on-premises Exchange today and most of those who struggled to cope with the need to manage Exchange Server have likely moved to the cloud. In other words, the organizations that run Exchange Server today are experienced and know their stuff. Even so, the transition to a subscription edition is unlikely to be seamless and will experience some glitches. Starting to prepare early and keeping abreast of news from the engineering group and community are good ways to lessen the chance of problems. Good luck!

About the Author

Tony Redmond

Tony Redmond has written thousands of articles about Microsoft technology since 1996. He is the lead author for the Office 365 for IT Pros eBook, the only book covering Office 365 that is updated monthly to keep pace with change in the cloud. Apart from contributing to Practical365.com, Tony also writes at Office365itpros.com to support the development of the eBook. He has been a Microsoft MVP since 2004.

Comments

  1. Ike Smith

    The Real Person!

    Author Ike Smith acts as a real person and verified as not a bot.
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    The Real Person!

    Author Ike Smith acts as a real person and verified as not a bot.
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    No disrespect intended, but then why isn’t Windows subscription based? That same logic should apply to EVERY software Microsoft makes, but it doesn’t…hence why i smell a rat

  2. ExchangeFan

    The Real Person!

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    The Real Person!

    Author ExchangeFan acts as a real person and verified as not a bot.
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    Well, i buy a exchange server CU15 in some months. And later, in less than 1 year, there are mails that doesnt arrive to an internet recipient that is in Azure. Its impossible Microsoft do it. Countrys lawers can make buyers return the product to Microsoft because its defective. A mail server product that cannot send mails. Its a defective product. In Spain, if i buy a product today, it must runs 2 years without problems. Software included. If Microsoft doesnt want Microsoft Exchange Server 2019 CU15 continue in use, they cannot to sell it.

    Its possible to do Microsoft hybrid settings not possible. If an organization want to use Microsoft Exchange Server SE, all exchange servers must be exchange Server SE. No anyone can use Microsoft Exchange Server SE with an edge Microsoft Exchange Server 2019 CU15. It is possible to do for Microsoft.

    Exactly equal than other software manufacturer that makes a version program incompatible with earlier versions.

    1. Avatar photo
      Tony Redmond

      I’m pretty sure that the Microsoft lawyers have made their terms of service water tight in respect of requiring customers to upgrade servers to the latest version as a condition for support. But feel free to take a case against Microsoft in Spain or somewhere else. I have experience of working with Microsoft (not for Microsoft) in major legal cases and I think you’ll find the experience very revealing.

  3. Wayne

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    Yearly cost?

    1. Avatar photo
      Tony Redmond

      Same as Exchange Server CALs today, if that’s what you buy, or Exchange Online licenses, if that’s what you prefer. The thing is that you must stay compliant with licensing requirements to receive updates.

  4. Nav UK

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    The Real Person!

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    Great info will send emails to my Small Business Clients who just do not want to go to cloud.

    If Exchange Subscription is Microsoft road map then there should be an option for like Mailbox only for £1 per mailbox per user. My many small business clients (small as 1 or 2 users) only need emails and do not need OFFICE.com or OWA etc.
    First Microsoft killed Small Business Server which which was cost effective for small business that have less than 10 users. Now they are killing on-prem. Not everyone want to place their mailboxes in the cloud.
    There should be a simple Exchange without OWA, only on-prem mailbox and connection to Outlook and smartphones for small businesses. Not everyone can afford £5 + vat per user.

    1. Avatar photo
      Tony Redmond

      There are many other options if you don’t want to put your mailboxes in the cloud. You don’t need to use Exchange Server. But if you do, you will use SE enentually and pay for security updates etc. Quite how you secure the alteratives is entirely up to you.

  5. Ike Smith

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    The Real Person!

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    I hope the lawfirm i do i.t. for sues microsoft for this. They should have to support 2019 for the same length of time as past exchange servers. Sub scription business models are pure garbage and ms needs knocked down a notch

    1. Avatar photo
      Tony Redmond

      I doubt anyone will attempt an action here. Microsoft has been very clear when the support window for Exchange 2019 terminates, so no one can argue that they are trying to pull a fast one. In addition, they can argue that moving to a model that requires customers to maintain software to ensure that the software is safe. It would be difficult for a lawyer to convince a judge that allowing customers to run insecure software when an alternative exists is a good thing.

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