diff --git a/django_comments_xtd/api/frontend.py b/django_comments_xtd/api/frontend.py
index 10dffd0a..fb15d5a3 100644
--- a/django_comments_xtd/api/frontend.py
+++ b/django_comments_xtd/api/frontend.py
@@ -12,6 +12,10 @@
 )
 
 
+COMMENTS_FOR_CONCRETE_MODEL = \
+    getattr(settings, 'COMMENTS_FOR_CONCRETE_MODEL', True)
+
+
 XtdComment = get_comment_model()
 
 
@@ -59,9 +63,11 @@ def _reverse(*args, **kwargs):
         return reverse(*args, **kwargs)
 
     form = CommentSecurityForm(obj)
-    ctype = ContentType.objects.get_for_model(obj)
+    ctype = ContentType.objects.get_for_model(
+        obj, for_concrete_model=COMMENTS_FOR_CONCRETE_MODEL,
+    )
     queryset = XtdComment.objects.filter(content_type=ctype,
-                                         object_pk=obj.pk,
+                                         object_pk=obj._get_pk_val(),
                                          site__pk=get_current_site_id(request),
                                          is_public=True)
     ctype_slug = "%s-%s" % (ctype.app_label, ctype.model)
@@ -86,10 +92,10 @@ def _reverse(*args, **kwargs):
         "flag_url": _reverse("comments-flag", args=(0,)),
         "list_url": _reverse('comments-xtd-api-list',
                              kwargs={'content_type': ctype_slug,
-                                     'object_pk': obj.id}),
+                                     'object_pk': obj._get_pk_val()}),
         "count_url": _reverse('comments-xtd-api-count',
                               kwargs={'content_type': ctype_slug,
-                                      'object_pk': obj.id}),
+                                      'object_pk': obj._get_pk_val()}),
         "send_url": _reverse("comments-xtd-api-create"),
         "preview_url": _reverse("comments-xtd-api-preview"),
         "form": {
diff --git a/django_comments_xtd/api/serializers.py b/django_comments_xtd/api/serializers.py
index 71d004f2..5661abc0 100644
--- a/django_comments_xtd/api/serializers.py
+++ b/django_comments_xtd/api/serializers.py
@@ -1,5 +1,4 @@
 from django.apps import apps
-from django.contrib.contenttypes.models import ContentType
 from django.contrib.sites.shortcuts import get_current_site
 from django.utils import formats, timezone
 from django.utils.html import escape
@@ -210,7 +209,7 @@ def validate(self, data):
         elif data['flag'] == 'report':
             option = 'allow_flagging'
         comment = data['comment']
-        ctype = ContentType.objects.get_for_model(comment.content_object)
+        ctype = comment.content_type
         key = "%s.%s" % (ctype.app_label, ctype.model)
         if not get_app_model_options(content_type=key)[option]:
             raise serializers.ValidationError(
diff --git a/django_comments_xtd/models.py b/django_comments_xtd/models.py
index 8d92af99..cec258ac 100644
--- a/django_comments_xtd/models.py
+++ b/django_comments_xtd/models.py
@@ -220,6 +220,10 @@ def get_comment_dict(obj):
         return dic_list
 
 
+XtdComment.content_object.for_concrete_model = \
+    getattr(settings, 'COMMENTS_FOR_CONCRETE_MODEL', True)
+
+
 def publish_or_unpublish_nested_comments(comment, are_public=False):
     qs = get_model().norel_objects.filter(~Q(pk=comment.id),
                                           parent_id=comment.id)
diff --git a/django_comments_xtd/utils.py b/django_comments_xtd/utils.py
index aa138f70..5b429c0c 100644
--- a/django_comments_xtd/utils.py
+++ b/django_comments_xtd/utils.py
@@ -14,7 +14,6 @@
     from urllib import urlencode
 
 from django.core.mail import EmailMultiAlternatives
-from django.contrib.contenttypes.models import ContentType
 from django.contrib.sites.shortcuts import get_current_site
 from django.utils.crypto import salted_hmac
 
@@ -86,7 +85,7 @@ def get_app_model_options(comment=None, content_type=None):
             default = copy(settings.COMMENTS_XTD_APP_MODEL_OPTIONS['default'])
 
     if comment:
-        content_type = ContentType.objects.get_for_model(comment.content_object)
+        content_type = comment.content_type
         key = "%s.%s" % (content_type.app_label, content_type.model)
     elif content_type:
         key = content_type
diff --git a/django_comments_xtd/views.py b/django_comments_xtd/views.py
index 3b4e186c..ee653be0 100644
--- a/django_comments_xtd/views.py
+++ b/django_comments_xtd/views.py
@@ -391,7 +391,7 @@ def flag(request, comment_id, next=None):
         get_comment_model(), pk=comment_id,
         site__pk=get_current_site_id(request))
     if not get_app_model_options(comment=comment)['allow_flagging']:
-        ctype = ContentType.objects.get_for_model(comment.content_object)
+        ctype = comment.content_type
         raise Http404("Comments posted to instances of '%s.%s' are not "
                       "explicitly allowed to receive 'removal suggestion' "
                       "flags. Check the COMMENTS_XTD_APP_MODEL_OPTIONS "
@@ -423,7 +423,7 @@ def like(request, comment_id, next=None):
     comment = get_object_or_404(get_comment_model(), pk=comment_id,
                                 site__pk=get_current_site_id(request))
     if not get_app_model_options(comment=comment)['allow_feedback']:
-        ctype = ContentType.objects.get_for_model(comment.content_object)
+        ctype = comment.content_type
         raise Http404("Comments posted to instances of '%s.%s' are not "
                       "explicitly allowed to receive 'liked it' flags. "
                       "Check the COMMENTS_XTD_APP_MODEL_OPTIONS "
@@ -459,7 +459,7 @@ def dislike(request, comment_id, next=None):
     comment = get_object_or_404(get_comment_model(), pk=comment_id,
                                 site__pk=get_current_site_id(request))
     if not get_app_model_options(comment=comment)['allow_feedback']:
-        ctype = ContentType.objects.get_for_model(comment.content_object)
+        ctype = comment.content_type
         raise Http404("Comments posted to instances of '%s.%s' are not "
                       "explicitly allowed to receive 'disliked it' flags. "
                       "Check the COMMENTS_XTD_APP_MODEL_OPTIONS "