The Exchange Team released the June updates for Exchange Server 2013 and 2016, and an additional Rollup 22 for Exchange Server 2010 Service Pack 3.

Apart from fixes and time zone changes, these updates contain the following important changes and notes:

• As announced earlier, Exchange 2013 CU21 and Exchange 2016 CU10 require .NET Framework 4.7.1.
• All three updates require the VC++ 2013 runtime library, because it is needed by a 3rd component in WebReady Document Viewing in Exchange 2010/2013 and Data Loss Prevention in Exchange 2013/2016. Exchange 2010 SP3 RU22 will force installation of this VC++ runtime.
• Updates include a critical security patch for Oracle Outside In libraries. More about the issue in MSRC advisory ADV180010.
• Exchange 2013 CU21 and Exchange 2016 CU10 introduce support for directly creating and enabling remote shared mailboxes, e.g.

  New-RemoteMailbox [-Shared] [-Name remoteMailboxName]
  Enable-RemoteMailbox [-Identity user] [-Shared] [-RemoteRoutingAddress user@domain]
  Set-RemoteMailbox [-Name user] [-Type Shared]

  You need to run setup /PrepareAD to see these changes. More information in KB4133605.

• This is the last planned Cumulative Update for Exchange 2013 as it enters Extended Support.
• Exchange 2010 SP3 RU22 adds support for Windows Server 2016 Domain Controllers.

Exchange 2016 CU10 fixes:

• 4056609 Event ID 4999 and mailbox transport delivery service won’t start with Exchange Server 2016 CU7 installed
• 4133605 Cmdlets to create or modify a remote shared mailbox in an on-premises Exchange environment
• 4133620 “HTTP 500 due to ADReferralException” error when a user tries to view detail properties of mailboxes in a child domain in Exchange Server
• 4095974 “System.InvalidOperationException” occurs when the “Enable-MailPublicFolder” cmdlet is run against a public folder in Exchange Server
• 4095973 Set-ServerComponentState cmdlet does not honor the write scope defined in the RBAC management scope in Exchange Server
• 4095993 HTTP 500 error when an administrator tries to manage regional settings in ECP on Windows Server 2016
• 4294209 Cannot clear the “Maximum message size” check box for Send messages or Receive messages in EAC in Exchange Server 2016
• 4294208 “TooManyObjectsOpenedException” error when you run the “Get-PublicFolderMailboxDiagnostics” cmdlet in Exchange Server
• 4294212 Cannot send VBScript-created messages in the Outlook 2016 client
• 4294211 Cannot run “Set-CalendarProcessing” cmdlets after you apply CU8 or CU9 for Exchange Server 2016
• 4294210 Cannot edit an email attachment in OWA in an Exchange Server 2016 environment
• 4294204 Changing “IsOutOfService” to “False” in an earlier Exchange Server version does not immediately update in a later Exchange Server environment
• 4092041 Description of the security update for Microsoft Exchange Server 2013 and 2016: May 8, 2018

Exchange 2013 CU20 fixes:

• 4133605 Cmdlets to create or modify a remote shared mailbox in an on-premises Exchange environment
• 4133604 User can’t log on to a POP/IMAP account by using NTLM authentication in Exchange Server 2013
• 4133618 Unexpected error occurs when running the Get-DatabaseAvailabilityGroupNetwork cmdlet in Exchange Server 2013
• 4133620 “HTTP 500 due to ADReferralException” when a user tries to view detail properties of mailboxes in a child domain in Exchange Server
• 4058473 An Office 365 primary mailbox user cannot be assigned full access permissions for an on-premises mailbox in Exchange Server
• 4094167 The MSExchangeRPC service crashes with a System.NullReferenceException exception in Exchange Server 2013
• 4095974 “System.InvalidOperationException” occurs when the “Enable-MailPublicFolder” cmdlet is run against a public folder in Exchange Server
• 4092041 Description of the security update for Microsoft Exchange Server 2013 and 2016: May 8, 2018
• 4294205 POP3 services intermittently stop in an Exchange Server 2013 environment
• 4294204 Changing “IsOutOfService” to “False” in an earlier Exchange Server version does not immediately update in a later Exchange Server environment

Exchange 2010 Rollup 22 fixes:

• 4295751 EWS impersonation not working when accessing resource mailboxes in a different site in Exchange Server 2010 SP3

Notes:

• Exchange 2016 CU8 and Exchange 2013 CU18 do not contain schema changes compared to their previous Cumulative Update. However, they introduce RBAC changes in your environment. Use setup /PrepareAD to apply RBAC changes, before deploying or updating Exchange servers.
• 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.
• When upgrading your Exchange 2013 or 2016 installation, don’t forget to put the server in maintenance mode when required. 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 stay at most one version behind (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, i.e. 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 in which you upgrade servers with Cumulative Updates is irrelevant.

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.