I already updated few days ago, but if I remember well, this didn’t worked back then either:
$ apt-get upgrade lxc-docker
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
Package lxc-docker is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'lxc-docker' has no installation candidate
I managed to update by removing the old version and reinstall the new one.
$ apt-get purge lxc-docker*
$ curl -fsSL https://get.docker.com/ | sh
Last command took forever to complete. At one point I started to worry, but after ~20 mins it was up & running.
I’m not saying this is the way of upgrading, but this was the way worked for me.
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.4 LTS