In a new post from Lukas Smith's blog he talks about the project's move to Subversion and away from CVS and how that's affected the language's development in a very positive way.
I remember that back when I was co-RM for PHP 5.3 one of the very painful parts was the crying and moaning about the commit freezes we put into place while packaging up a new release. The reason being we were on CVS, if people kept committing while a release was being tested it would effectively prevent any sort of QA.
Because of problems like this (and many others), the group decided to drop CVS for their development and head to the brighter land of Subversion. So, instead of having days when no commits are allowed, correct branching and testing make it much easier to develop one of the web's most popular languages.
The change came with some new branching techniques and some of the developers in the group aren't as happy about how they're handled. Some new tools have been developed to help minimize the risks that these methods could cause, though, including this site.