So, it would seem that update rollup 6 had been released but all the links all went dead shortly after release.
If you managed to download it prior to it's removal (like I did) please be weary of installing it until Microsoft re-releases it.
I haven't tried to install it and I don't know if there is anything wrong with it but please hold off unless you have a test-bed instance that you are willing to destroy if you managed to get a copy prior to it's removal.
For updates on the UR status please follow the following Microsoft CRM forum thread:
I am sure Microsoft will figure out what is going on soon and all will be well, but make sure you get a new version.
Also, here is a podcast related to what is changing in Update Rollup 6 for all those who are interested.