[German]Microsoft released hotfix updates (HU) for Exchange Server 2016 and 2019 on April 24. These hotfix updates provide support for new features and are intended to resolve issues caused by the March 2024 Security Update (SU). Although the updates are optional, they bring some benefits to Exchange administrators (e.g. support for ECC certificates, Hybrid Modern Authentication (HMA) for OWA/ECP).
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German blog reader 12gang pointed out the release of the hotfix update in this comment (thanks for that) – I also came across the following tweet from the Exchange team about the hotfix updates for Exchange Server 2016 and Exchange Server 2019.
Microsoft has published the Techcommunity article Released: April 2024 Exchange Server Hotfix Updates with a description of the hotfix updates. Hotfix updates (HU) are available for the following Exchange Server CU versions.
HUs are available as a self-extracting .exe package. The hotfix updates do not fix any vulnerabilities, but bring a number of small new features.
The new features in the April 2024 HU
The April 2024 hotfix updates (HU) introduce support for ECC (Elliptic Curve Cryptography) certificates and hybrid modern authentication for Outlook on the web and ECP.
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Support for ECC certificates
As of the April 2024 HU, Exchange Server 2016 and Exchange Server 2019 now support ECC certificates, except when used in Active Directory Federation Services (AD FS) scenarios.
Hybrid modern authentication (HMA) for OWA/ECP
Microsoft has also announced that Hybrid Modern Authentication (HMA) for OWA/ECP will also be supported from April 2024 HU. This feature requires Exchange 2019 CU14 + April 2024 HU (or later). Further information can be found in the feature documentation.
Problems fixed with the hotfix updates
Microsoft lists in the Techcommunity post Released: April 2024 Exchange Server Hotfix Updates lists a number of issues that have been reported since the release of the March 2024 security updates for Exchange Server. The following issues in the March 2024 SUs are addressed in this April 2024 HU:
- Download domains not working after installing the March 2024 SU
- "We can't open this document" error in OWA after installing March 2024 SU
- Search error in Outlook cached mode after installing March 2024 SU
- OwaDeepTestProbe and EacBackEndLogonProbe fail after installing March 2024 SU
- Edit permissions option in the ECP can't be edited
- Outlook doesn't display unread message icon after installing Exchange Server March 2024 SU (Note: the fix resolves this issue for new messages, after April 2024 HU or later is installed)
- My Templates add-in isn't working after installing Microsoft Exchange Server March 2024 SU
- Published calendars might not work with a "This calendar isn't available" error after installing March 2024 SU
Some unresolved issue from March 2024 SU: Printing calendars in OWA may not work if the keyboard shortcut CTRL+P is not used. Microsoft wants to fix this in a future update. The tech community post also contains an FAQ about the hotfix update, which points out, among other things, that the April 2024 HU is an optional update that does not have to be installed, but brings some bug fixes and new features. In addition, there are already comments from administrators with feedback on the first minor bugs.
Similar articles:
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Microsoft has fixed an Exchange EWS issue from March 14, 2024 on Macs
Problems with Microsoft Outlook and Exchange since March 2024 patch day? – Part I
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