You probably got the “experimental” version because that’s what everyone gets if they initially installed via curl https://get.docker.com | sh. You have to change /etc/apt/sources.list.d/docker.list to track the stable repo rather than edge or whatever the default is.
Being conservative in upgrading docker isn’t even enough; we follow that policy (still on 17.06), and we still got hit by a ripper of a bug that exists in all versions from 17.06 to 17.11 (and, by the glacial pace at which the PR is moving, will probably be in 18.01 or whatever the next release will be).
Basically, Docker’s gonna Docker, and all we can do is hang on for the ride and try and dodge the worst of the low-hanging tree branches.