9/6 - Pre-release1 out (binaries and tar balls), testing begins 9/12 - Pre-release1 testing ends 9/20 - Pre-release2 testing begins 9/26 - Pre-release2 testing ends 9/28 - Release!
There will be more information as the branch date approaches. Please have all major features finished as soon as possible. It's important to have them fully tested before we go into the release period.
Note, 9/3 is not the final date for code submissions. However, as the release process continues, the criteria for accepting patches will become more and more strict. (During the pre-release2 phase, we will accept only those patches which fix regressions from 2.7.)