Today, the Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. The fixes in each release, product downloads are described below:

Version	Build	KB	Download	UMLP	Schema
Exchange 2019 CU3	15.2.464.5	KB4514141	VLSC		N
Exchange 2016 CU14	15.1.1847.3	KB4514140	Download	UMLP	N

Exchange 2019 CU3 fixes:

• 4515257 Hash mismatch is reported for Exchange DLLs in the bin directory of Exchange Server 2019
• 4502159 Adding or removing mailbox permission in EAC doesn’t address the msExchDelegateListLink attribute in Exchange Server 2019 and 2016
• 4515276 Room mailbox accepts a meeting as “Free” if a booking delegate is set in Exchange Server 2019 and 2016
• 4515275 Enable Get/Restore-RecoverableItems to work with Purges folder in Exchange Server 2019 and 2016
• 4515274 AutodiscoverV2 request returns REST API endpoint not AutoDiscoverV1 endpoint in Exchange Server 2019 and 2016
• 4515269 SentToMemberOf shows every recipient type not distribution groups when you create transport rule in Exchange Server 2019 and 2016
• 4515272 Message is blocked in “SMTP Delivery to Mailbox” queue if exchange server is added in groups of a child domain in Exchange Server 2019 and 2016
• 4515271 Can’t convert a migrated remote user mailbox to shared in Exchange Server 2019 and 2016
• 4515270 SubmissionQueueLengthMonitor shows “System.ArgumentException: Transition timeout…” in Exchange Server 2019 and 2016
• 4515267 NDR occurs when you resend message from alternate journaling mailbox to journaling mailbox in Exchange Server 2019 and 2016
• 4515265 Removing In-Place Hold doesn’t work for mailboxes in different domains in Exchange Server 2019 and 2016
• 4515264 FindPeople request from Skype for Business on Mac fails with “Invalid Shape Specification” in Exchange Server 2019 and 2016
• 4515263 Hide the “Validate-MailFlowThroughFrontDoor” command for Exchange Server 2019 and 2016
• 4515262 Enable Remove-MobileDevice to delete mobile devices after migrating to Office 365 from Exchange Server 2019 and 2016
• 4515261 Can’t copy eDiscovery search results for mailboxes with Exchange online archives in Office 365 in Exchange Server 2019 and 2016
• 4515273 Mailbox auditing fails when using SHA1Managed in Exchange Server 2019 and 2016
• 4515266 Infinite loop in Recurrence.GetNumberOfYearsBetween() with the Japanese calendar in Exchange Server 2019 and 2016
• 4520319 S/MIME signed reply draft behaves like the first message in conversation in Exchange Server 2019 and 2016
• 4515832 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 10, 2019

Exchange 2016 CU14 fixes:

• 4515255 “X-InnerException: Microsoft.Mapi.MapiExceptionRpcServerTooBusy” error when you try to use a mailbox in Exchange Server 2016
• 4515254 Event 1009 frequently occurs in application logs for lagged database copies in Exchange Server 2016
• 4502159 Adding or removing mailbox permission in EAC doesn’t address the msExchDelegateListLink attribute in Exchange Server 2016
• 4515276 Room mailbox accepts a meeting as “Free” if a booking delegate is set in Exchange Server 2016
• 4515275 Enable Get/Restore-RecoverableItems to work with Purges folder in Exchange Server 2016
• 4515274 AutodiscoverV2 request returns REST API endpoint not AutoDiscoverV1 endpoint in Exchange Server 2016
• 4515269 SentToMemberOf shows every recipient type not distribution groups when creating transport rule in Exchange Server 2016
• 4515272 Message is blocked in “SMTP Delivery to Mailbox” queue if exchange server is added in groups of a child domain in Exchange Server 2016
• 4515271 Can’t convert a migrated remote user mailbox to shared in Exchange Server 2016
• 4515270 SubmissionQueueLengthMonitor shows “System.ArgumentException: Transition timeout…” in Exchange Server 2016
• 4515267 NDR occurs when you resend message from alternate journaling mailbox to journaling mailbox in Exchange Server 2016
• 4515265 Removing In-Place Hold doesn’t work for mailboxes in different domains in Exchange Server 2016
• 4515264 FindPeople request from Skype for Business on Mac fails with “Invalid Shape Specification” in Exchange Server 2016
• 4515263 Hide the “Validate-MailFlowThroughFrontDoor” command for Exchange Server 2016
• 4515262 Enable Remove-MobileDevice to delete mobile devices after migrating to Office 365 from Exchange Server 2016
• 4515261 Can’t copy eDiscovery search results for mailboxes with Exchange online archives in Office 365 in Exchange Server 2016
• 4515273 Mailbox auditing fails when you use SHA1Managed in Exchange Server 2016
• 4515266 Infinite loop in Recurrence.GetNumberOfYearsBetween() with the Japanese calendar in Exchange Server 2016
• 4520319 S/MIME signed reply draft behaves like the first message in conversation in Exchange Server 2016
• 4515832 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 10, 2019

Notes:

• These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
• When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
• Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
• When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to delay installing at most one version (n-1).
• If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
• Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
• Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
• The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.