{% load humanize %}
{% spaceless %}
    {% with obj as release %}
        {{ release.comic.name|safe }}
        published {{ release.pub_date|naturalday }}
    {% endwith %}
{% endspaceless %}

{% load humanize %}
{% spaceless %}
    {% with obj as release %}
        {{ release.comic.name|safe }}
        published {{ release.pub_date|date }}
    {% endwith %}
{% endspaceless %}

Use a date format that does not change with time in feed titles
Use a date format that does not change with time in feed titles
