Last Friday, Microsoft released a blog post announcing a delay in the upcoming Exchange 2019 CU15, also known as Exchange 2019 H1 2025 CU.

This blog post also mentions support for Exchange 2019 CU14 running on Windows 2025, including Windows 2025 Domain Controllers. This can be very interesting if you are planning to move to Exchange 2019 CU15 and later this year to Exchange Server SE.

Installing CU14 on Windows 2025 works fine. The only difference is the prerequisite roles and features. Since Windows 2025 no longer supports the native SMTP stack and the legacy MMC snap-in, these need to be removed from the installation commands.

Use the following command to install the prerequisite roles and features:

Install-WindowsFeature Server-Media-Foundation, NET-Framework-45-Core, NET-Framework-45-ASPNET, NET-WCF-HTTP-Activation45, NET-WCF-Pipe-Activation45, NET-WCF-TCP-Activation45, NET-WCF-TCP-PortSharing45, RPC-over-HTTP-proxy, RSAT-Clustering, RSAT-Clustering-CmdInterface, RSAT-Clustering-Mgmt, RSAT-Clustering-PowerShell, WAS-Process-Model, Web-Asp-Net45, Web-Basic-Auth, Web-Client-Auth, Web-Digest-Auth, Web-Dir-Browsing, Web-Dyn-Compression, Web-Http-Errors, Web-Http-Logging, Web-Http-Redirect, Web-Http-Tracing, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Metabase, Web-Mgmt-Console, Web-Mgmt-Service, Web-Net-Ext45, Web-Request-Monitor, Web-Server, Web-Stat-Compression, Web-Static-Content, Web-Windows-Auth, Web-WMI, Windows-Identity-Foundation, RSAT-ADDS, Telnet-Client

The Telnet client is optional but can be very useful for troubleshooting purposes.

All other prerequisite software needed for CU14 is identical to Windows 2019 or Windows 2022 and so is installing the Exchange 2019 CU14 software itself.

Important note. Yesterday I had some issues installing the Security Update For Exchange Server 2019 CU14 SU3 V2 (KB5049233) and reported this to Microsoft. This morning I installed a new Windows 2025 server, installed all the prerequisites and Exchange 2019 CU14, and this time the SU installation succeeded without issues.

But as with every software update, test in your own lab before rolling out into production!