Wave 15 of Office products reached the Release To Manufacturing (RTM) stage today, October 11, 2012 (10/11/12 - heh).
These products include Exchange Server 2013, Lync Server 2013, SharePoint Server 2013, and Microsoft Office 2013.
Note that RTM, also known as "code-complete", means that development is done on the products and they will now be written to ISOs, DVDs burned, retail boxes built, etc.
This does NOT mean that the releases are currently available. As of today, releases are still only available to TAP and RDP participants.
General Availability (GA) defines the timeframe when the releases will be available to everyone. This is targeted for first quarter calendar-year 2013 for all the Wave 15 products.
However, volume license customers will be able to download these products on the Volume Licensing Service Center (VLSC) by mid-November and the products will be on the VL price lists starting December 1, 2012.
Specifically for Exchange, the build number for the RTM release is 15.0.516.32. Exchange 2013 was code-named E15 throughout its development cycle.
For your information, "Wave 15" refers to the fact that version numbers of all Office product lines have been synchronized. The major version number for all products is "15".
For more information about Exchange, refer to the Exchangae team blog: The New Exchange Reaches RTM!
For more information about the other Office products, refer to the Office blog: Office Reaches RTM.
It is interesting to note that both releases refer to "the New Exchange" and "the new Office" - taking a cue from Apple, I presume; in not tying the announcement to a specific release of the product.
Today Microsoft released Security Advisory 2749655, Compatibility Issues Affecting Signed Microsoft Binaries. I encourage you to read the security advisory. We also saw that Exchange team post the following blog entry Re-released Exchange 2010 and Exchange 2007 update rollups. Microsoft re-released the rollups in order to ensure that third party programs are not impacted by the security advisory.
That is, Microsoft re-released the updates as a pre-emptive measure - just in case.
If you have installed the security advisory, you really don't need to re-install the updates. Quoting from the security advisory:
What does this update do?
This update will help to ensure the continued functionality of all software that was signed with a specific certificate that did not use a timestamp Enhanced Key Usage (EKU) extension. To extend their functionality, WinVerifyTrust will ignore the lack of a timestamp EKU for these specific X.509 signatures.
Note regarding the impact of not installing a rereleased update
Customers who installed the original updates are protected from the vulnerabilities addressed by the updates. However, because improperly signed files, such as executable images, would not be considered correctly signed after the expiration of the CodeSign certificate used in the signing process of the original updates, Microsoft Update may not install some security updates after the expiration date. Other effects include, for example, that an application installer may display an error message. Third-party application whitelisting solutions may also be impacted. Installing the rereleased updates remediates the issue for the affected updates.
Long story short - Microsoft has released the updates "just in case".
Given that Exchange 2010 SP2 Update Rollups can take upwards of an hour to install and your Exchange server is offline while you doing the installation - you may just want to wait for the next UR.
Please note: the Exchange 2010 SP2 UR4 re-release does include one new patch. You can install that separately in a very short timeframe: Outlook only returns one result after you click the "Your search returned a large number of results. Narrow your search, or click here to view all results" message.