...
As of 2016, recommendation is (investigating)... to use Ubuntu Managed. The Ubuntu powers that be do a decent job of keeping the Docker version up to date and do follow best practices outlined in the Docker setup (ie using a distinct group).
Running a Ubuntu Managed install resulted in Docker 1.11.2 build b9f10c9 which from the Docker release notes was submitted on Jun 1 2016. In comparison, directly results in 1.12.0 build 8eab29e. At the time the most up to date is Docker 1.12.1 build 0dc92ee.
...