Sometime this spring, though for the life of me I can’t find it, I wrote a blog post where I said I thought Update 3 (VS/TFS 2012.3) would be the last update in the VS/TFS 2012 update line. I often say that nothing that is said about the future is more than a guess with varying levels of confidence. So, it turns out that I was wrong. A month or two ago we decided that we were going to need to do a 2012.4 release.
The primary motivation is addressing compatibility and migration/round-tripping issues between VS 2012 and VS 2013 and the various platform releases to make adoption of VS 2013 as smooth as possible. The planned timing will be around the same time VS 2013 releases (and, of course, I can’t give any more detail at this time other than saying that it will be before the end of the year). Once we decide to ship a release like this, it then becomes a vehicle to deliver anything else that would be valuable/important to deliver in that timeframe. So, for instance Update 4 will also include a roll up of fixes for all important customer reported by the time it locks down.
Like Update 3, Update 4 will be a very scoped release just focused on these compatibility fixes and key customer impacting bug fixes. We will not be delivering significant new features in Update 4. I qualify it with “significant” because what is a feature and what is a bug fix is in the eye of the beholder.
Today we released the first Release Candidate for Update 4. Don’t take the “Release Candidate” designation too seriously. We’re going to have several release candidates and it’s still early in the process. I think the primary reason for calling it a release candidate is that we have validated it for production use and we wanted the name to clearly reflect that. So if you’ve got a specific issue that’s addressed in this release, installing it would make sense. Otherwise, I would just wait a little bit for a later release candidate. I’d say that, at this point, less than half the fixes that will ultimately be in the release are in this release candidate.
Here are some resources for RC1:
You’ll find the specific list of bug fixes so far in the KB article. You’ll also notice most of them are TFS related at this point 
So now you are going to ask me whether or not there will be an Update 5. At this point, my answer will be “If we need one.” But, I don’t expect so at this time.
Enjoy!
Brian