After the release of Visual Studio 2012 Update 3 (RTM) in 26th June, Microsoft released the 4th Update to the web today, the 13th November 2013. Within this timeframe, they also released couple of intermediate release of the Update 4 for beta testing and bug fixes.
This includes the latest cumulative series of feature additions and bug fixes. If you are waiting for the final release of Update 4, it’s the time to update your IDE with latest set of features & fixes.