diff --git a/docker/meta/sphinx.yml b/docker/meta/sphinx.yml
index f4571d3..203eb0c 100644
--- a/docker/meta/sphinx.yml
+++ b/docker/meta/sphinx.yml
@@ -7,7 +7,7 @@
       name: host
       param:
         version:
-          value: "{{ salt['cmd.shell']('docker --version', python_shell=True) }}"
+          value: "{{ salt['cmd.shell']('docker --version 2>/dev/null || echo unknown', python_shell=True) }}"
     {%- endif %}
     {%- if pillar.docker.swarm is defined %}
     {%- from "docker/map.jinja" import swarm with context %}