Today the Exchange Team released Rollup 4 for Exchange Server 2010 Service Pack 2 (KB2706690). This update raises Exchange 2010 version number to 14.2.318.2.

Here’s the list of changes in this Rollup:

• 2536846 Email messages sent to a mail-enabled public folder may be queued in a delivery queue on the Hub Transport server in an Exchange Server 2010 environment
• 2632409 Sent item is copied to the Sent Items folder of the wrong mailbox in an Exchange Server 2010 environment when a user is granted the Send As permission
• 2637915 “550 5.7.1” NDR when an email message is sent between tenant organizations in a multi-tenant Exchange Server 2010 environment
• 2677727 MRM cannot process retention policies on a cloud-based archive mailbox if the primary mailbox is in an on-premises Exchange Server 2010 organization
• 2685001 Retention policies do not work for the Calendar and Tasks folders in an Exchange Server 2010 SP1 environment
• 2686540 Journal report is not delivered to a journaling mailbox in an Exchange Server 2010 environment
• 2689025 Performance issues when you use the light version of Outlook Web App in an Exchange Server 2010 environment
• 2698571 Some email messages are not delivered when you set the MessageRateLimit parameter in a throttling policy in an Exchange Server 2010 environment
• 2698899 Add-ADPermission cmdlet together with a DomainController parameter fails in an Exchange Server 2010 environment
• 2700172 Recipient’s email address is resolved incorrectly to a contact’s email address in an Exchange Server 2010 environment
• 2701162 User A that is granted the Full Access permission to User B’s mailbox cannot see detailed free/busy information for User B in an Exchange Server 2010 environment
• 2701624 ItemSubject field is empty when you run the Search-MailboxAuditLog cmdlet together with the ShowDetails parameter in an Exchange Server 2010 environment
• 2702963 The “Open Message In Conflict” button is not available in the conflict notification message in Exchange Server 2010
• 2707242 The Exchange Information Store service stops responding on an Exchange Server 2010 server
• 2709014 EdgeTransport.exe process crashes intermittently on an Exchange Server 2010 server
• 2709935 EdgeTransport.exe process repeatedly crashes on an Exchange Server 2010 server
• 2713339 Multi-Mailbox Search feature returns incorrect results when you perform a complex discovery search in an Exchange Server 2010 environment
• 2713371 Throttling policy throttles all EWS applications in Exchange Server 2010
• 2719894 The Microsoft Exchange RPC Client Access service consumes 100 percent of CPU resources and stops responding on an Exchange Server 2010 Client Access server
• 2723383 Incorrect time zone in a notification when the Resource Booking Attendant declines a meeting request from a user in a different time zone in an Exchange Server 2010 environment
• 2724188 A subject that contains colons is truncated in a mixed Exchange Server 2003 and Exchange Server 2010 environment
• 2726897 Event 14035 or Event 1006 is logged when Admin sessions are exhausted in an Exchange Server 2010 environment

In addition to these fixes, this Rollup also includes a fix for the WebReady security issue described in Microsoft Security Bulletin MS12-058 (KB2740358).

Note that  This Rollup includes changes enabling Retention Tags for Calendar Items and Tasks (see KB2685001). If you wish to retain pre-SP2RU4 functionality, implement the following registry key on each Mailbox server:
HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeMailboxAssistants\Parameters\ELCAssistantCalendarTaskRetentionEnabled=0x00000000 (REG_DWORD); default value is 1. More information on possible implications at the Exchange Team’s blog here.

Important: Be advised that it is reported that installing MS12-058 (KB2740358) means Rollup 4 will be installed on your system. This applies to manual installations but updates installed through Windows Update / WSUS as well, which might pose a challenge (or better, dilemma) for security departments (Thanks to Paul Bendall).

Those who use WSUS to deploy security updates or manually apply MS12-058 will be inadvertently applying Exchange 2010 SP2 RU4 as the security

As of this Rollup, its no longer required to disable/re-enable ForeFront Protection for Exchange using the fscutility to be able to install the Rollup properly. However, if you want to remain in control, you can disable ForeFront before installing the Rollup using fscutility /disable and re-enable it afterwards using fscutility /enable.

Note that Rollups are cumulative, i.e. they contain fixes released in earlier Rollups for the same product level (RTM, SPx). This means you don’t need to install previous Rollups during a fresh installation but can start with the latest Rollup.

As with any Hotfix, Rollup or Service Pack, I’d recommend to thoroughly test this rollup in a test and acceptance environment first, prior to implementing it in production. For the correct procedure on how to update DAG members, check here.

You can download Exchange 2010 SP2 Rollup 4 here.