Microsoft corrects Exchange problems in March updates with hotfix

Microsoft has released hotfix updates for Exchange Server. They are intended to correct some of the problems that the March security update for Exchange brought with it. New functions have also been added.

A blog post in Microsoft's tech community from the Exchange team provides details on the hotfixes. The hotfixes are available for Exchange Server 2019 CU 13 (Hotfix Update For Exchange Server 2019 CU13 HU6, KB5037224) and CU14 (Hotfix Update For Exchange Server 2019 CU14 HU2, KB5037224) as well as for Exchange Server 2016 CU23 (Hotfix Update For Exchange Server 2016 CU23 HU13, KB5037224).

Exchange hotfix with new functions

The April hotfix update provides support for Elliptic Curve Cryptography (ECC) certificates for Exchange 2016 and 2019. Microsoft mentions one restriction: Elliptic curves are not available in Active Directory Federation Services (AD FS) environments. Exchange 2019 CU14 also supports Hybrid Modern Authentication (HMA) for Outlook Web Access, more precisely OWA/ECP, with the April hotfix. Microsoft also provides instructions for configuration.

The following errors that may occur after installing the security updates from March should also be corrected by the hotfixes:

• Download domains no longer work
• "We cannot open this document" error in OWA
• Search error in Outlook in cached mode
• OwaDeepTestProbe and EacBackEndLogonProbe fail
• "Edit permissions" option in ECP cannot be edited
• Outlook does not show an "unread envelope" icon (only for new messages that arrive after applying the hotfix)
• My templates add-in does not work
• Published calendars do not work with an error message "This calendar is not available"

A problem with printing calendars in OWA, which can only be triggered by the key combination Ctrl+P, remains unsolved.

The hotfixes are optional updates. They are cumulative: anyone who skipped the March update will also receive the security fixes in the April hotfix.

(dmk)