SP2 contains a number of performance-based improvements for Outlook users. Pain points which were addressed include starting up and shutting down Outlook, switching between folders with large numbers of messages, calendar reliability and consistency, and general responsiveness when performing common tasks around managing e-mail, calendar, and other information. In short, Outlook should run faster and be more responsive, with fewer crashes.
The developers put a lot of effort into fixing calendar bugs. Users will see fewer duplicate copies of meetings and fewer issues with organizers and attendees having different versions of the same meeting. They should have fewer problems with disappearing and reappearing meetings. Outlook should also do a better job at automatically resolving conflicting edits without generating copies of the items in the Conflicts folder.
The first time you run Outlook after installing this update, there will be a delay while Outlook reprocesses your data files. This processing happens the first time your profile is opened in Outlook and can take a few seconds to a few minutes, depending on the size of your message store. After this initial process, performance should be noticeably improved.
Note that additional file types were added to the blocked extension list. They are: .cnt, .osd, .vbp, and .hpj file extensions.
Also note that if you use the Outlook Live Connector 12.1, you may have duplicate Calendar and Contacts items if all Outlook clients used to access the account are not upgraded to SP2.
While the cumulative update doesn't have any truly "new" features, some old features were updated or fixed. Whether you call them new features or bug fixes, the changes should be welcomed by users.
The one "new feature" I think every Outlook user will love: the ability to set a print range. This one was a long time coming, since Outlook 97 to be exact.
Ctrl+Insert now works to Copy text in the Reading pane.
A previously announced change involves issues shutting down Outlook when third party add-ins or utilities are installed. Outlook will do a better job at shutting down completely and you can say good-bye to checking the Tasks Manager after closing Outlook to verify it's really closed. See https://msdn.microsoft.com/en-us/library/dd239276.aspx for more information.
Another helpful feature: the Infobar on messages in the Junk folder will tell you if Outlook's Junk mail filter put the message in the folder or it arrived there by another method. The "other methods" include third party anti-spam software and Outlook's blocked sender list. This should make it easier to troubleshoot false positives, or at least, allow you to rule out (or blame) an overzealous junk email filter.
The distribution list size was increased from 99 to unlimited for Exchange accounts.
A number of issues that caused duplicate items were addressed, including issues involving RSS items, SharePoint items, and meeting requests. In fact, several bugs related to meeting requests were fixed, as were most of the calendar bugs I've written about in past issues of EMO.
Although this doesn't qualify as a new feature, I do want to mention the time zone update tool was removed from Outlook. If you need to update appointments with new time zones, download the tool from Microsoft. Microsoft has recommended using the downloadable tool instead of the built in tool, since not long after the release of Outlook 2007.
Download the 2007 Microsoft Office suite Service Pack 2 package
Outlook 2007 improvements in the 2007 Office suite Service Pack 2
Outlook 2007 improvements in the February 2009 cumulative update
Description of the Outlook 2007 hotfix package (Outlook.msp): February 24, 2009
Download for the February 2009 cumulative update
Outlook 2007: New information in the InfoBar for messages in the Junk E-Mail folder
Description of the Outlook 2007 hotfix package (Outlook-en-us.msp): February 24, 2009
This update addresses an issue with accelerator keys in the web browser control when embedded in a mail form. Install it after installing the cumulative update. This is also required for page range printing and large DL capability.
Exchange Messaging Outlook February 26 2009