diff --git a/wagtail_adminsortable/__init__.py b/wagtail_adminsortable/__init__.py
index 7fd229a..0404d81 100644
--- a/wagtail_adminsortable/__init__.py
+++ b/wagtail_adminsortable/__init__.py
@@ -1 +1 @@
-__version__ = '0.2.0'
+__version__ = '0.3.0'
diff --git a/wagtail_adminsortable/mixins.py b/wagtail_adminsortable/mixins.py
index 7feeb1d..f14eb11 100644
--- a/wagtail_adminsortable/mixins.py
+++ b/wagtail_adminsortable/mixins.py
@@ -11,14 +11,14 @@ class AjaxableResponseMixin(object):
     """
     def form_invalid(self, form):
         response = super(AjaxableResponseMixin, self).form_invalid(form)
-        if self.request.is_ajax():
+        if self.request.accepts("application/json"):
             return JsonResponse(form.errors, status=400)
         else:
             return response
 
     def form_valid(self, form):
         super(AjaxableResponseMixin, self).form_valid(form)
-        if self.request.is_ajax():
+        if self.request.accepts("application/json"):
             objects = json.loads(self.request.POST.get('objects', '[]'))
             data = {
                 'message': 'success'