On May 3, 2023, Microsoft unveiled Cumulative Update 13 (KB5020999) for Exchange Server 2019, commonly referred to as Exchange Server 2019 CU13. This update addresses both security and non-security concerns by incorporating fixes for existing issues. In addition to resolving non-security issues, it encompasses all previously released solutions for both security and non-security matters. Furthermore, the fixes included in Cumulative Update 13 will be integrated into subsequent Cumulative Updates for Exchange Server 2019.Cumulative Update CU13 for Exchange Server 2019 is identified by the version number 15.02.1258.012.
How to update Exchange Server 2019 to CU13?
Updating Exchange Server 2019 to CU13 involves several steps. It is advisable to perform the update initially in a lab environment before executing it in the production setting.
- Download Cumulative Update CU13 for Exchange Server 2019 (KB5020999)
- Update to Microsoft .NET Framework 4.8
- If its already installed, you will receive a message that its already installed on your server
- For example not required with Windows Server 2022 as its already installed.
- Install Exchange Cumulative Update
Known issues in Cumulative Update 13
In Active Directory forests with multiple domains where Exchange is either installed or has been prepared using the /PrepareDomain option in Setup previously, it is crucial to execute this action after the /PrepareAD command for the current cumulative update has been executed and the modifications have been replicated across all domains. The /PrepareAD command will be automatically attempted during the initial server installation, and the installation process will only conclude successfully if the initiating user possesses the necessary permissions.
New Features in Cumulative Update 13:
- Installation Experience Improvements:
- Enhancements have been made to facilitate Cumulative Update installations.
- Previously, CUs would overwrite configuration files (e.g., web.config and sharedweb.config), leading to the loss of custom settings, such as client-specific message size limits.
- To mitigate this issue, Setup now automatically backs up the most common configuration settings during installation and restores them to their pre-setup state.
- Starting with the 2023 H1 CU, Setup preserves approximately 70 different configuration settings across various files.
Issues fixed in Cumulative Update 13
This Cumulative Update fixes the issues that are described in the following Microsoft Knowledge Base articles:
- 5026134 “InvalidRecipientsException” when you try to run MRM
- 5026135 CertificateDeploymentServicelet failure in multiple domain forest Exchange deployments
- 5026136 Microsoft Exchange Transport doesn’t re-encrypt IRM messages
- 5026138 Users receive reminders although the meeting reminder is set to None
- 5026139 You can’t move the public folder mailbox
- 5026142 Journal message returns “ConversionFailedException”
- 5026143 OAB shadow distribution threshold must be reduced or made configurable
- 5026146 Expiry notification is sent to moderator and sender for approved and delivered messages
- 5026147 BlockLegacyAuthentication fail Organization Policy because of BackendRehydrationModule implementation
- 5026149 Group metrics generation doesn’t finish in multidomain environment
- 5026150 Edge server Filtering Agent removes journal attachments
- 5026151 Oab-Processing-Threshold is set to 0 for On-Premises
- 5026152 Microsoft Exchange ActiveSync or Current Requests counter inaccurately counts requests
- 5026153 Delivery Flow Control setting override is now available
- 5026154 On-premises Exchange has 35MB file size limit for online archiving
- 5026155 “No support for this operation” error on an Exchange 2019 DAG member server
- 5026156 Outlook search fails in a shared On-Premises mailbox if the primary user mailbox is migrated to Exchange Online
- 5026158 The body of recurring meeting is not clear if it has Chinese characters
- 5026159 IconIndex returns Default value when Server Assisted Search is used in Outlook
- 5026266 “Could not start MS Exchange Service Host service” error and Exchange stops responding
- 5026267 OWA stops responding in an Exchange 2019 and 2016 coexistence topology
- 5026268 Store Worker process crashes and returns “System.NullReferenceExceptions” multiple times per day
- 5026269 Block deserialization error when using eDiscovery
- 5026271 IIS URL Rewrite Module link is incorrect
- 5026273 Outlook configuration fails in Android or iOS
- 5026274 Hybrid Agent Validation fails after Extended Protection is enabled
- 5026277 Mail configuration fails on iOS device after Extended Protection is enabled
- 5026278 Mailbox migration fails after Extended Protection is enabled
In summary, Cumulative Update 13 (KB5020999) for Exchange Server 2019, released on May 3, 2023, addresses security and non-security issues, with version number 15.02.1258.012. Follow the outlined steps for a smooth update, including the download of CU13, updating Microsoft .NET Framework 4.8, and installing the update. Notable features include enabling Modern Auth for On-Premises Exchange users.
Be cautious of known issues, especially in multi-domain Active Directory forests, where executing /PrepareDomain after /PrepareAD is crucial. The update resolves various issues, such as the “InvalidRecipientsException” and Outlook configuration problems.
In essence, Cumulative Update 13 ensures a more secure and improved Exchange Server 2019 environment.
