From the Exchange team blog as the KB articles are not online yet.
The Exchange team is announcing the availability of the following updates:
- Update Rollup 5 for Exchange Server 2010 Service Pack 3
- Update Rollup 13 for Exchange Server 2007 Service Pack 3
Exchange Server 2010 Service Pack 3 Update Rollup 5 resolves customer reported issues and includes previously released security bulletins for Exchange Server 2010 Service Pack 3. A complete list of the issues resolved in this rollup is available in KB2917508.
Exchange Server 2007 Service Pack 3 Update Rollup 13 provides recent DST changes and adds the ability to publish a 2007 Edge Server from Exchange Server 2013. Update Rollup 13 also contains all previously released security bulletins and fixes and updates for Exchange Server 2007 Service Pack 3. More information on this rollup is available in KB2917522.
Neither release is classified as a security release but customers are encouraged to deploy these updates to their environment once proper validation has been completed.