The Docker version of the distributions are often quite old. On Ubuntu 16.04 for example:
shell> docker --version
Docker version 1.13.1, build 092cba3
But the current docker version is 17.09.0-ce (2017-09-26). It seems like they have switched from the old version schema x.y.z
to the new year.month.version
version schema in February/March 2017.