I don't think this is possible with the predefined variables since they only contain CI_RUNNER_DESCRIPTION, CI_RUNNER_ID and CI_RUNNER_TAGS.

You could create a workaround by using the environment setting in the runner config.toml as described in this section and the example:

[[runners]]
  name = "ruby-2.1-docker"
  url = "https://CI/"
  token = "TOKEN"
  limit = 0
  executor = "docker"
  builds_dir = ""
  shell = ""
  environment = ["ENV=value", "CI_RUNNER_VERSION=10.2"]
  clone_url = "http://gitlab.example.local

If you use stuff like Ansible, Puppet, Chef or another provisioning tool you could make sure they update the config when they upgrade the runner e.g.

Or create a bash script that replaces the CI_RUNNER_VERSION value in the config.toml based on a every day/night and restarts the runner service. That would be pretty easy.

You can get the version or your runner (and only the exact version) by running:

$ gitlab-runner --version | head -n 1 | awk '{print $2}'

I have updated my server to GitLab 6.6.4 and finally found the way to get version of GitLab remotely without SSH access to server.

You should be logged in to access the following page: https://your.domain.name/help

It shows something similar to:

GitLab 6.6.4 42e34ae

GitLab is open source software to collaborate on code.
...
etc.