From Larian's twitter:
"We rolled a Nat 1 on our patch release check today, as we found some pesky bugs that we don't want to release into the wild. We've decided to delay the release of Patch 5 until Thursday this week so we can fix these issues for you."
They posted it on Twitter, but could not bother posting a note here on their own forums? Not everyone is a twitter twit (someone that uses twitter).