Microsoft's Exchange Server Subscription Edition is here

The Exchange Server Subscription Edition is now generally available. On Tuesday, Microsoft released the successor to the last locally installable Exchange Server 2019.

Microsoft's Exchange developers have now announced its availability in a blog post. This means that a locally installable "on-premises" version of Exchange will remain and customers can choose whether they prefer to move to the cloud to Microsoft 365 or Exchange Online – or even set up a hybrid operation.

Microsoft Exchange: upgrade paths

In the article, they also explain the available migration paths once again. Since Exchange 2016 and 2019, like Windows 10, will reach the end of their support on October 14, 2025, it is imperative to migrate to newer Exchange versions – Security vulnerabilities in Exchange servers are regularly and quickly attacked by criminals.

A direct migration can be made from Exchange Server 2019 CU14 or CU15 to the Exchange Server Subscription Edition Release-To-Manufacturing (RTM) version in the form of a cumulative update. Microsoft has already announced this for the Windows 11 25H2 desktop operating system, which can be upgraded from Windows 11 24H2 with minimal effort by activating Enablement Packages. Exchange Server SE should be able to be integrated into Exchange 2016/2019 environments. For Exchange 2016, however, this requires a "classic" mailbox migration, Microsoft explains further.

Further details can be found in a somewhat older article from Microsoft. The migration transfers the local Exchange server to the"Modern Support Lifecycle", a model in which Microsoft continuously develops and supports the software, provided that customers always use the latest version. Unlike previous Exchange RTM releases, Exchange Server SE does not contain any major code changes or other customizations compared to Exchange 2019, so Microsoft only sees a low risk in an "in-place upgrade". The main differences include new license terms, the name change from Microsoft Exchange Server 2019 to Microsoft Exchange Server Subscription Edition and updated build and version numbers (Exchange Server SE RTM: 15.02.2562.017). In addition, updates that have been released since Exchange 2019 CU15 are also included in Exchange SE RTM – and this remains the case with every CU update.

Microsoft makes it obvious once again: The RTM release of Exchange SE is identical to Exchange 2019 CU5, except for the differences mentioned above. But it will not stay that way. After the end of support for Exchange 2016 and 2019, Exchange SE will remain the only supported on-premises version. This gives Microsoft the opportunity to simplify, streamline and modernize the product in the coming years. Microsoft plans to continue with two CUs per year and security patches or hotfixes as required.

Microsoft recommends migrating to Exchange SE RTM as soon as possible and decommissioning older Exchange 2016 and 2019 servers. The CU2 for Exchange SE already does not support Exchange 2016 and 2019 servers in the organization. Future Exchange SE CUs will "modernize" the installation requirements and require Exchange SE server keys – and bring new features.

Skype for Business: Subscription Edition

In a final paragraph, Microsoft mentions in passing that the Skype for Business Server Subscription Edition is now also available for those who have requirements for several on-premises servers. Despite all the announcements, Skype is apparently not really coming to an end.

(dmk)