The Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. Like recent Cumulative Updates for these products, they require .NET Framework 4.8. Apart from fixes as well as security updates included from the previous CU, the Exchange 2019 CU7 also comes with an update for the Exchange Sizing Calculator.

Links to the updates as well as a description of changes and fixes are described below.

Version	Build	KB	Download	UMLP	Schema	PrepareAD
Exchange 2019 CU7	15.2.721.2	KB4571787	VLSC		N	Y
Exchange 2016 CU18	15.1.2106.2	KB4571788	Download	UMLP	N	Y

Exchange 2019 CU7 fixes:

• 4570248 Get-CASMailbox uses wrong LDAP filter for ECPEnabled in Exchange Server 2019
• 4576652 Updates for Exchange Server 2019 Sizing Calculator version 10.5
• 4570252 Intermittent poison messages due to NotInBagPropertyErrorException in Exchange Server 2019
• 4576649 System.InvalidCastException when you change passwords in Outlook on the web in Exchange Server 2019
• 4570251 Inbox rule applying a personal tag doesn’t stamp RetentionDate in Exchange Server 2019
• 4570245 ESEUtil /p fails if any long value (LV) is corrupted in Exchange Server 2019
• 4570255 NullReferenceException occurs when running TestFederationTrust in Exchange Server 2019
• 4576650 Can’t add remote mailbox when setting email forwarding in Exchange Server 2019 Hybrid environment
• 4570253 CompletedWithErrors without details for mailbox migration batches in Exchange Server 2019
• 4570247 CSV log of Discovery export fails to properly escape target path field in Exchange Server 2019
• 4570246 EdgeTransport crashes with Event ID 1000 (exception code 0xc00000fd) in Exchange Server 2019
• 4570254 MSExchangeMapiMailboxAppPool causes prolonged 100% CPU in Exchange Server 2019
• 4563416 Can’t view Online user free/busy status in Exchange Server 2019
• 4576651 Can’t join Teams meetings from Surface Hub devices after installing Exchange Server 2019 CU5
• 4577352 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 8, 2020

Exchange 2016 CU18 fixes:

• 4570248 Get-CASMailbox uses wrong LDAP filter for ECPEnabled in Exchange Server 2016
• 4570252 Intermittent poison messages due to NotInBagPropertyErrorException in Exchange Server 2016
• 4576649 System.InvalidCastException when you change passwords in Outlook on the web in Exchange Server 2016
• 4570251 Inbox rule applying a personal tag doesn’t stamp RetentionDate in Exchange Server 2016
• 4570245 ESEUtil /p fails if any long value (LV) is corrupted in Exchange Server 2016
• 4570255 NullReferenceException occurs when you run TestFederationTrust in Exchange Server 2016
• 4576650 Can’t add remote mailbox when setting email forwarding in Exchange Server 2016 Hybrid environment
• 4570253 CompletedWithErrors without details for mailbox migration batches in Exchange Server 2016
• 4570247 CSV log of Discovery export fails to properly escape target path field in Exchange Server 2016
• 4570246 EdgeTransport crashes with Event ID 1000 (exception code 0xc00000fd) in Exchange Server 2016
• 4570254 MSExchangeMapiMailboxAppPool causes prolonged 100% CPU in Exchange Server 2016
• 4563416 Can’t view Online user free/busy status in Exchange Server 2016
• 4576651 Can’t join Teams meetings from Surface Hub devices after installing Exchange Server 2016 CU16
• 4577352 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 8, 2020

Notes:

• These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
• There are Active Directory changes requiring you to run PrepareAD. Consult the Exchange schema versions page for object version numbers.
• 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 allowed to trail 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.