Vagrant 1.4.1 has been released. This is a bug-fix release for Vagrant 1.4.0 and is a safe drop-in upgrade for all Vagrant 1.4 users. Vagrant 1.4.0 has been the most stable release so far in the 1.x series and we're happy to make a bug-fix release to make it even more reliable.
One notable improvement is that the Docker provisioner now works with RedHat-based guest machines. The remainder of changes are bug fixes.