After pulling Rollup 4 for Exchange Server 2010 SP1 on July 13th, after potential data loss issues were discovered during folders movements, and publishing an intermediate hotfix to resolve the RU4 issues without a rollup rerelease, the Exchange team decided to publish an updated version of rollup 4. This is somehow unexpected because of the expected release of rollup 5 in August. It’s good to see the Exchange team getting very open in this post about recent missteps in published rollups for such a mission critical application.
Exchange 2010 SP1 Rollup 4 v2 raises Exchange 2010′s version number to 14.1.323.6 (initial release was 14.1.323.1). The related knowledgebase article is kb2579150.
For the correct procedure on how to update a DAG and its members, check here.
You can download Exchange 2010 SP1 Rollup4 v2 here.