I noticed that the latest stable 17.06-ce release is not on apt.dockerproject.org:
http://apt.dockerproject.org/repo/pool/main/d/docker-engine/
The 17.06-ce release is available on download.docker.com
https://download.docker.com/linux/ubuntu/dists/xenial/pool/stable/amd64/
I have been using apt.dockerproject.org to create an internal mirror using apt-mirror of the docker deb packages to make local installations more reliable. I did not see a notice that apt.dockerproject.org was deprecated. Was this an oversight or should I change my mirror scripts to use download.docker.com now?