We will push only stabilizing bug fixes to the 5.6 branch, so it will stay compatible with the 5.6.0 RC/release packages. All new features are pushed to the dev/5.7 branch. Technically 5.7 is already feature frozen when the branch gets created, but modules previously stamped as tech previews have an exception so we can continue the development full speed. We still got plenty of things to do before we have earned the final stamp. :)