title: Version in "./docker-compose.yml" is unsupported. You might be seeing this error because you're using the wrong Compose file version
body: <p>Here's my docker-compose.yml file:</p>
  
  <pre><code>version: '3.1'
  
  services:
    a:
      image: tutum/hello-world
    b:
      image: tutum/hello-world
  
  secrets:
    id: my_password
  </code></pre>
  
  <p>If I run <code>$ docker-compose-up</code> I get this:</p>
  
  <blockquote>
    <p>Version in "./docker-compose.yml" is unsupported. You might be seeing this error because you're using the wrong Compose file version.</p>
  </blockquote>
  
  <p>My docker-compose version: </p>
  
  <pre><code>$ docker-compose --version
  docker-compose version 1.11.0, build 6de1806
  </code></pre>
  
  <p>What's wrong here? Shouldn't my docker-compose version support v3.1 of the docker-compose.yml specification (according to the <a href="https://github.com/docker/compose/releases" rel="noreferrer">release notes</a>, it does) ?</p>