sol2/sphinx_rtd_theme/versions.html

{% if READTHEDOCS %}
  <div class="rst-versions" data-toggle="rst-versions">
    <span class="rst-current-version {% if current_version != "latest" %}rst-out-of-date{% endif %}" data-toggle="rst-current-version">
      <span class="float-left icon icon-book"> Read the Docs</span>
      v: {{ current_version }} 
      {% if current_version != "latest" %}(old) {% endif %}
      <span class="icon icon-caret-down"></span>
    </span>
    <div class="rst-other-versions">
      <dl>
        <dt>Version</dt>
        {% for slug, url in versions %}
          <dd><a href="{{ url }}">{{ slug }}</a></dd>
        {% endfor %}
      </dl>
      <dl>
        <dt>Downloads</dt>
        {% for type, url in downloads %}
          <dd><a href="{{ url }}">{{ type }}</a></dd>
        {% endfor %}
      </dl>
      <hr/>
      Free document hosting provided by <a href="http://www.readthedocs.org">Read the Docs</a>.
    </div>
  </div>
{% endif %}