Update Rollup 5 for System Center 2012 R2 has just been released, this KB article contains full information around the included fixes. The article also contains the installation instructions and download link.

A fix I am glad to see in here is the one around Specified cast is not valid when opening run as account properties which is an issue I blogged about 2 years ago.

All in all this seems like a good update, as always test before going live.