Exchange Server 2010 Service Pack 3 (SP3) has been released, raising the Exchange version number to 14.3.123.4.

For those still unaware, the 550 MB file (1.45 GB uncompressed) contains the full set of binaries; you can use it to upgrade existing installations or deploy new Exchange 2010 SP3 installations.

Service Pack 3 introduces the following features:

• Exchange 2013 Coexistence
  This Service Pack for Exchange 2010 adds coexistence with Exchange 2013. However, for coexistence Exchange Server 2013 Cumulative Update 1 (CU1) is required, which hasn’t been released yet.
• Windows Server 2012 Support
  This Service Pack enables you to deploy Exchange Server 2010 on WIndows Server 2012 platform.
• Internet Explorer 10
  You can now use Internet Explorer 10 to connect to Exchange 2010.
• Sent Items Management
  You can now control behavior of Send-As or Send-on-Behalf messages regarding the folder used to store a copy of the sent message, analogue to the Delegated Send Items options available in Outlook.

In addition to fixes that were part of the Exchange 2010 SP2 Rollups 1 to version 6, SP3 adds the following fixes:

• 2552121 You cannot synchronize a mailbox by using an Exchange ActiveSync device in an Exchange Server 2010 environment
• 2729444 Mailboxes are quarantined after you install the Exchange Server 2010 SP2 version of the Exchange Server 2010 Management Pack
• 2778100 Long delay in receiving email messages by using Outlook in an Exchange Server 2010 environment
• 2779351 SCOM alert when the Test-PowerShellConnectivity cmdlet is executed in an Exchange Server 2010 organization
• 2784569 Slow performance when you search a GAL by using an EAS device in an Exchange Server 2010 environment
• 2796950 Microsoft.Exchange.Monitoring.exe process consumes excessive CPU resources when a SCOM server monitors Exchange Server 2010 Client Access servers
• 2800133 W3wp.exe process consumes excessive CPU and memory resources on an Exchange Client Access server after you apply Update Rollup 5 version 2 for Exchange Server 2010 SP2
• 2800346 Outlook freezes and high network load occurs when you apply retention policies to a mailbox in a mixed Exchange Server 2010 SP2 environment
• 2810617 Can’t install Exchange Server 2010 SP3 when you define a Windows PowerShell script execution policy in Group Policy
• 2787500 Declined meeting request is added back to your calendar after a delegate opens the request by using Outlook 2010
• 2797529 Email message delivery is delayed on a Blackberry mobile device after you install Update Rollup 4 for Exchange Server 2010 SP2
• 2800080 ErrorServerBusy response code when you synchronize an EWS-based application to a mailbox in an Exchange Server 2010 environment

Be advised that after installing SP3 on Mailbox servers, the databases are upgraded to the SP3 version database schema. An SP3 database can’t be mounted on pre-SP3 Mailbox servers. Keep this in mind when upgrading your DAG (you will temporarily have limited fail-over/fall-back or switch-over options) or for example when utilizing database portability. Note that upgrading databases can be time consuming, especially with RTM or low SP databases as the database will be upgrade using interim steps, i.e. RTM to SP1, SP1 to SP2 and finally SP2 to SP3.

Also, while Exchange Server 2010 SP3 is supported on Windows Server 2012, that doesn’t mean .NET 4.5 (WMF 3.0, PowerShell 3.0) is supported on Windows Server 2008 or Windows Server 2008 R2; on Windows Server 2012, PowerShell 2.0 will be used. Also, OS upgrades (e.g. WS2008 R2 to WS2012) with Exchange installed aren’t supported.

After preparing your forest for Exchange 2010 SP3, the schema version number will have changed. Check the Schema Versions page for information on the new values for Exchange 2010 SP3.

The proper method to upgrade mailbox servers that are a member of a Database Availability Group is described here.

You can download Exchange 2010 SP3 here.

The UM language packs for SP3 can be downloaded here. Note that you need to uninstall previous UM language packs before you can install the SP3 versions.