Technically, you can see these 'release', 'openbeta', 'openalpha' as update channels which the builds of DCS are distributed through. We call these - branches.
So, for example, build 1.5.2.48726.137 was released to the openbeta branch first. And yesterday we pushed the very same build to the release branch.
They are essentially the same build of the DCS, byte-identical.