Today the Exchange Team released Rollup 15 for Exchange Server 2007 Service Pack 3 (KB2996150). This update raises Exchange 2007 version number to 8.3.389.2.

This Rollup contains a security update to fix a potential elevation of privilege issue (bulletin MS14-075), as well as the following fixes:

• 3004235 Exchange Server meetings in Russian time zones as well as names of time zones are incorrect after October 26, 2014
• 3008308 Public folder database migration issue in a mixed Exchange Server environment

Notes:

• When running ForeFront Protection for Exchange, make sure you disable ForeFront before installing the rollup and re-enable it afterwards, otherwise the Information Store and Transport services may not start. You can disable ForeFront using fscutility /disable and enable it using the fscutility /enable command;
• 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;
• Rollups are cumulative per service pack level, i.e. they contain fixes released in earlier update Rollups for the same product level (RTM, SP). This means you don’t need to install previous Rollups during a fresh installation but can start with the latest Rollup package.

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.
You can download Exchange 2007 SP3 Rollup 15 here.