dictionary update sequence element #0 has length 1; 2 is required. Error during template rendering

Question

This question has been asked before, but the answer given doesn't seem to work for me... I have:

ValueError at /myapp/
dictionary update sequence element #0 has length 1; 2 is required

Error during template rendering

In template ~/Software/myproject/myapp/templates/myapp/base.html, error at line 53
dictionary update sequence element #0 has length 1; 2 is required

base.html

<a class="brand" href="{% url "about" %}">About page</a>

Error

 File "~/Software/myproject/myapp/views/basic.py", line 380, in idx_order
    return render(request, 'myapp/index_other.html', {'orders': orders, 'orders_done': orders_done, 'STATUS_CHOICES': dSTATUS_CHOICES})

views.py

def idx_order(request):
    orders = Order.objects.all().order_by('status','deadline','created','lastUpdate').exclude(status=2)
    orders_done = Order.objects.all().order_by('status','deadline','created','lastUpdate').filter(status=2)

    return render(request, 'myapp/index_other.html', {
        'orders': orders, 
        'orders_done': orders_done, 
        'STATUS_CHOICES': dSTATUS_CHOICES
        })

def about(request):
    """
    Function outputs user and system credentials to an about.html page depending on whether DEBUG = True/False. 
    """
    if settings.DEBUG == True:
        do stuff

        return render(request, 'myapp/about.html', 
            {'list_zero': list_zero,
                'list_one': list_one, 
                'installed_packages_list': library_dict
            })
    else:    
        return HttpResponse("You shouldn't be here :o)")

urls.py

urlpatterns = [
    url(r'^$', idx_order, name='idx_order'),
    url(r'^about/$', about, name='about'),

I'm performing an update from Django1.8 to 1.11. I'm racking my brains about this but can't see where my mistake could lie.