Windows Server 2025 was released on November 1, 2024 and is the fifteenth and current major version of the Windows NT operating system produced by Microsoft.
In Windows Server 2025 there are many security improvements integrated so that this new operating system is future-proof again. Although there are many improvements to report, this article focuses only on Hotpatching.
Hot patching
Until now, it was necessary to restart the servers after each monthly patch round to make the patches active for the operating system. This causes downtime for the applications, databases and websites if they are not redundant in some form.
Hotpatching is a way to install security updates without having to restart the server. If there is for example a Cumulative Update in January, then there will be Hotpatch releases for February and March. However, it is still the case that a reboot is necessary to install updates that are not part of the Hotpatch program, although less frequently.
Updates that are not part of the Hotpatch program are e.g. Non-security updates, .NET updates and Non-Windows updates. These can be for example drivers and firmware updates.
The disadvantage of Hotpatch updates is that there is no support for automatic rollback. If a problem occurs during or after an update, the update must be removed manually and the latest functional baseline update must be installed. These manual actions require a restart of the server.