diff --git a/Changelog b/Changelog
index 6b8b1370..d3c2c549 100644
--- a/Changelog
+++ b/Changelog
@@ -1,6 +1,7 @@
 Next:
     * #3911: [dcl] Integrate resend activation link into dcl landing payment page
     * #3972: [hosting] Add ungleich company info to invoice footer
+    * #3974: [hosting] Improve invoice number: Show 404 for invoice resources that do not belong to the user
 1.2.13: 2017-12-09
     * [cms] Introduce UngleichHeaderBackgroundImageAndTextSliderPlugin that allows to have scrolling images and texts
     * [cms] Remove <p> tag for ungleich cms customer item template
diff --git a/hosting/views.py b/hosting/views.py
index e1231dc5..1839f85b 100644
--- a/hosting/views.py
+++ b/hosting/views.py
@@ -671,13 +671,25 @@ class OrdersHostingDetailView(LoginRequiredMixin,
     permission_required = ['view_hostingorder']
     model = HostingOrder
 
-    def get_object(self):
-        return HostingOrder.objects.get(
-            pk=self.kwargs.get('pk')) if self.kwargs.get('pk') else None
+    def get_object(self, queryset=None):
+        order_id = self.kwargs.get('pk')
+        try:
+            hosting_order_obj = HostingOrder.objects.get(pk=order_id)
+            logger.debug("Found HostingOrder for id {order_id}".format(
+                order_id=order_id
+            ))
+        except HostingOrder.DoesNotExist:
+            logger.debug("HostingOrder not found for id {order_id}".format(
+                order_id=order_id
+            ))
+            hosting_order_obj = None
+        return hosting_order_obj
 
     def get_context_data(self, **kwargs):
         # Get context
-        context = super(DetailView, self).get_context_data(**kwargs)
+        context = super(
+            OrdersHostingDetailView, self
+        ).get_context_data(**kwargs)
         obj = self.get_object()
         owner = self.request.user
         stripe_api_cus_id = self.request.session.get('customer')
@@ -691,6 +703,17 @@ class OrdersHostingDetailView(LoginRequiredMixin,
             context['page_header_text'] = _('Confirm Order')
         else:
             context['page_header_text'] = _('Invoice')
+            if not self.request.user.has_perm(
+                    self.permission_required[0], obj
+            ):
+                logger.debug(
+                    "User {user} does not have permission on HostingOrder "
+                    "{order_id}. Raising 404 error now.".format(
+                        user=self.request.user.email,
+                        order_id=obj.id if obj else 'None'
+                    )
+                )
+                raise Http404
 
         if obj is not None:
             # invoice for previous order
diff --git a/requirements.txt b/requirements.txt
index 89285c83..2ff887a7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -67,7 +67,7 @@ lxml==3.6.0
 model-mommy==1.2.6
 phonenumbers==7.4.0
 phonenumberslite==7.4.0
-psycopg2==2.6.1
+psycopg2==2.7.1
 pycryptodome==3.4
 pylibmc==1.5.1
 python-dateutil==2.5.3
diff --git a/ungleich_page/locale/de/LC_MESSAGES/django.po b/ungleich_page/locale/de/LC_MESSAGES/django.po
index 873bb0df..affd285d 100644
--- a/ungleich_page/locale/de/LC_MESSAGES/django.po
+++ b/ungleich_page/locale/de/LC_MESSAGES/django.po
@@ -22,7 +22,7 @@ msgid "Glasfaser menu"
 msgstr ""
 
 msgid "\"Sorry, we could not find the page you are looking for!\""
-msgstr ""
+msgstr "\"Leider konnten wir die von dir gesuchte Seite nicht finden!\""
 
 msgid "Toggle navigation"
 msgstr "Umschalten"