Microsoft Exchange Server 2019 CU12

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

5012757 "Migration user… can't be found" error when using Start-MigrationUser after batch migration fails
5012758 Start-MailboxAssistant is not available in Exchange Server 2019
5012760 You can't access OWA or ECP after installing the July 2021 security update
5012761 External attendees see “Send the Response Now” although no response was requested in Exchange Server
5012762 PST creation is unexpectedly triggered again during multiple mailbox export
5012765 Email stuck in queue starting from "2022/1/1 00:01:00 UTC+0" on all Exchange on-premises servers
5012766 Transport Services fail repeatedly because of * Accepted Domain
5012768 Start-MigrationUser and Stop-MigrationUser are unavailable for on-premises Exchange Server 2019 and 2016
5012770 No response from public folder for users migrating to Microsoft Exchange 2019
5012772 Items are skipped at the start of a new search page request
5012773 OWAMailboxPolicy is bypassed and high resolution profile images can be uploaded
5012774 Can't change default path for Trace log data in Exchange Server 2019 and 2016
5012775 No additional global catalog column in the address book service logs
5012776 Exchange Server 2019 help link in OWA redirects users to online help for Exchange Server 2016
5012777 Can’t find forwarded messages that contain attachments in Exchange Server 2019
5012778 Exchange Server stops responding when processing PDF files with set transport rule
5012779 Invalid new auth certificate for servers that are not on UTC time zone
5012780 Disable-Mailbox does not remove LegacyExchangeDN attribute from on-premises Exchange 2019
5012781 Exchange Server 2019 and 2016 DLP doesn’t detect Chinese resident ID card numbers
5012782 MS ExchangeDiagnostic Service causes errors during service startup and initialization in Microsoft Exchange 2019
5012783 Can't restore data of a mailbox when LegacyDN is empty in the database5012784 Exchange 2016 CU21 and Exchange 2019 CU10 cannot save "Custom Attributes" changes in EAC
5012785 Read Only Domain Controllers (RODCs) in other domains do not get desired permissions
5012786 Forwarded meeting appointments are blocked or considered spam
5012787 Download domains created per CVE-2021-1730 don’t support ADFS authentication in OWA
5012789 Can't use Copy Search Results after eDiscovery & Hold search
5012790 OWA doesn’t remove the "loading" image when a message is opened in Chrome and Edge browsers
5012791 MailboxAuditLog doesn't work in localized (non-English) environments
5012829 Group metrics generation fails in multidomain environment

Security: Exchange Server 2019 requires Windows Server 2019. In fact, we recommend installing Exchange Server 2019 onto Windows Server 2019 Server Core. Exchange Server 2019 installed on Windows Server 2019 Core provides the most secure platform for Exchange. You also have the option of installing Exchange 2019 onto Windows Server 2019 with Desktop Experience, but we have worked hard to make sure running Exchange on Server Core is the best choice for our code.

We’re aware all media for Windows Server 2019 and Windows Server, version 1809 has been temporarily removed and Microsoft will provide an update when refreshed media is available. Exchange Server 2019 will be fully compatible with version 1809, and the refreshed version.

We also built Exchange Server 2019 to only use TLS 1.2 out of the box, and to remove legacy ciphers and hashing algorithms.

We’ve done significant work to allow Exchange Server to take advantage of larger core and memory packed systems available in market today. With our improvements, Exchange Server can use up to 48 processor cores and 256GB of RAM.

We’ve re-engineered search using Bing technology to make it even faster and provide better results, and in doing so have made database failovers much faster, and administration easier.

We’re adding dual storage read/write capabilities to Exchange Server 2019 using Solid State Drive (SSD) technology to provide a super-fast cache of key data for improving end user experience. We also talked about this in our Email Search in a Flash! Accelerating Exchange 2019 with SSDs session at Ignite.

We also changed the way database caching works to allocate more memory to active database copies, again improving the end user experience. You can learn more about Dynamic Database Cache from Welcome to Exchange Server 2019! video and slides.

The improvements we have made to Exchange Server 2019 will enable you to scale to a larger number of users per server than ever before, use much larger disks, and see the latency of many client operations being cut in half.

We all rely on Exchange for calendaring, and we know large enterprises are heavy calendar users. We are bringing a few key features such as restricting the forwarding of meeting requests and better control over OOF settings to Exchange Server 2019. Administrators get some new calendaring features too, as we’re adding the ability to manage events on user’s calendars and assign delegate permissions more easily.

We are also adding support for routing mail to and from EAI/IDN recipients and hope to add additional capabilities in this area in the future.