We have the DC/OS overlay on by default in DC/OS 1.8. The DC/OS overlay has a strict requirement of docker 1.11 to be operational. However, the upgrade guides for 1.8 do not mention any requirements for docker.
We need to explicitly call out this dependency. In case the customer cannot upgrade to docker 1.11, than the customer should explicitly disable the DC/OS overlay. The customer can disable DC/OS overlay by setting `dcos_overlay_enable: false` in his `config.yaml`.