order Notification list in base.html.twig symfony2

Question

I'm currently working on a symfony project that I didn't start , I'm finishing it so there are some parts that already made by someone else , my question is that in the application there's a nav bar for notification, I wanted to order the notification display by datetime using an attribute but I can't find the controller/action responsible for notification icon I only found the base.html.twig that contains the notification icon what can I do ?

<li class="dropdown">
  <a title="Notifications" href="#fakelink" class="dropdown-toggle"
     data-toggle="dropdown">
    <strong> 
      <i class="fa fa-bell">
      </i>
      {% set conge = 0 %}
      {% set notif = 0 %}
      {% set refuse = 0 %}
      {% for notif_c in notif_conges if notif_c.getEtat == "En cours" %}
        {% set conge = conge + 1 %}
      {% endfor %}
      {% for notif_c in notif_conges if notif_c.getEtat == "Acceptée" and notif_c.user == app.user %}
        {% set notif = notif + 1 %}
      {% endfor %}
      {% for notif_c in notif_conges if notif_c.getEtat == "Refusée" and notif_c.user == app.user %}
        {% set refuse = refuse + 1 %}
      {% endfor %}
      ({{ conge }})
    </strong>
  </a>
  {% if notif_conges|length > 0 %}
  <ul class="dropdown-menu animated half flipInX">
    {% for notif_c in notif_conges %}
    {% if notif_c.etat == "En cours" %}
    <li>
      <a>Nouvelle demande : "{{ notif_c.motif }}" Envoyée le
        "{{ notif_c.CreatedAt|date('Y-m-d H:i:s') }}" 
      </a>
    </li>
    {% endif %}
    {% if  notif_c.etat == "Acceptée" and notif_c.user == app.user %}
    <li>
      <a>Votre demande : "{{ notif_c.motif }}" Envoyée le
        "{{ notif_c.CreatedAt|date('Y-m-d H:i:s') }}" a était
        traitée 
      </a>
    </li>
    {% endif %}
    {% if  notif_c.etat == "Refusée" and notif_c.user == app.user %}
    <li>
      <a>Votre demande : "{{ notif_c.motif }}" Envoyée le
        "{{ notif_c.CreatedAt|date('Y-m-d H:i:s') }}" a était
        traitée 
      </a>
    </li>
    {% endif %}
    {% endfor %}
  </ul>
  {% endif %}
</li>