This cumulative update is a security update. It includes fixes for nonsecurity issues and all previously released fixes for security and nonsecurity issues.

Known issues in this cumulative update

• In multidomain Active Directory forests in which Exchange is installed or has been prepared previously by using the /PrepareDomain option in Setup, this action must be completed after the /PrepareAD command for this cumulative update has been completed and the changes are replicated to all domains. Setup will try to run the /PrepareAD command during the first server installation. Installation will finish only if the user who initiated Setup has the appropriate permissions.
  Notes:
  1. If you are upgrading from Cumulative Update 2 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019 to Cumulative Update 4 for Exchange Server 2019, then there’s no need to run the /PrepareAD or /PrepareDomain. No additional actions (prepareAD, prepareDomain, or assigning permissions) are required.
  2. If you has ever skipped a Cumulative Update (for example, you are upgrading from an earlier version before Cumulative Update 2 for Exchange Server 2019), or this is a first Exchange Server installation in the AD, then this Known Issue section should be taken care of.
     
     a. About the /PrepareDomain operation in multidomain:
     
     The /PrepareDomain operation automatically runs in the Active Directory domain in which the /PrepareAD commandis run. However, it may be unable to update other domains in the forest. Therefore, a domain administrator should run the /PrepareDomain in other domains in the forest.
     
     b. About the permission question:
     
     As the /PrepareAD is triggered in Setup, if the user who initiates Setup isn’t a member of Schema Admins and Enterprise Admins, the readiness check will fail and you receive the following error messages:
     
     
     To avoid the error messages, either the user should join Schema Admins and Enterprise Admins groups, or another user in Schema Admins and Enterprise Admins groups manually runs the /PrepareAD for this Cumulative Update first. Then the Exchange admin user can start Setup.
• Autodiscover Event ID 1 after installing Cumulative Update 3 for Exchange Server 2019. For more information, see KB 4532190.
• The Export-ModernPublicFolderStatistics.ps1 script doesn’t work in Microsoft Exchange Server 2019. For more information, see KB 4536552.

Issues that this cumulative update fixes

This cumulative update also fixes the issues that are described in the following Microsoft Knowledge Base articles:

• 4528696 Exchange PowerShell cmdlets take longer time to run in Exchange Server 2019
• 4528695 Event ID 4009 when using SubjectOrBodyMatchesPatterns on Edge server in Exchange Server 2019
• 4528694 Can’t open .ics file in Outlook on the web in Exchange Server 2019
• 4528692 “A parameter was specified that isn’t valid” error when creating transport rule in Exchange Server 2019
• 4523519 Set-SendConnector doesn’t work for Exchange Server in hybrid scenarios with Edge Server installed
• 4528688 Only one recipient shows when saving draft by using Exchange ActiveSync version 16.0 in Exchange Server 2019
• 4528693 Get-CalendarDiagnosticLog is proxied for queries within the same forest in Exchange Server 2019
• 4528687 NotificationClient logs aren’t purged and consume lots of disk in Exchange Server 2019
• 4528689 Outlook on the web shows MailTip when recipients equal the large audience size in Exchange Server 2019
• 4528690 Can’t move or delete folder in Outlook online mode if the destination has a folder with the same name in Exchange Server 2019
• 4532744 System.ArgumentNullException when you use Set-user to assign block legacy auth policy in Exchange Server 2019
• 4532747 Address list separation not working for a user without a mailbox in Exchange Server 2019
• 4523171 Description of the security update for Microsoft Exchange Server 2019, 2016, and 2013: November 12, 2019