diff --git a/.travis.yml b/.travis.yml
index 7224796..9bc0bb0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,17 @@
 language: python
 sudo: false
 python:
+ - "2.7"
  - "3.4"
+ - "3.5"
 env:
   global:
-   - DRF="djangorestframework==3.3.2"
-   - DJANGO="django==1.9.3"
+   - DRF="djangorestframework==3.4.5"
   matrix:
-   - LINT=
-   - LINT=1
+   - DJANGO="django==1.8.14"
+   - DJANGO="django==1.9.9"
+   - DJANGO="django==1.10"
+   - DJANGO="django==1.10" LINT=1
 install:
  - pip install $DJANGO
  - pip install $DRF
diff --git a/natural_keys/models.py b/natural_keys/models.py
index 6156ce8..e423953 100644
--- a/natural_keys/models.py
+++ b/natural_keys/models.py
@@ -125,7 +125,7 @@ def get_natural_key_info(cls):
         fields = cls.get_natural_key_def()
         info = []
         for name in fields:
-            field = cls._meta.get_field_by_name(name)[0]
+            field = cls._meta.get_field(name)
             rel_to = field.rel.to if field.rel else None
             info.append((name, rel_to))
         return info
diff --git a/tests/test_app/__init__.py b/tests/test_app/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_naturalkey.py b/tests/test_naturalkey.py
index c1d1e6f..5c1ac9e 100644
--- a/tests/test_naturalkey.py
+++ b/tests/test_naturalkey.py
@@ -75,17 +75,22 @@ def test_naturalkey_duplicate(self):
 class NaturalKeyRestTestCase(APITestCase):
     def test_naturalkey_rest_serializer(self):
         # Serializer should include validator
-        serializer = NaturalKeySerializer.for_model(NaturalKeyChild)
+        serializer = NaturalKeySerializer.for_model(NaturalKeyChild)()
         self.maxDiff = 10000000
         expect = """
              Serializer():
-                 parent = Serializer(required=True):
-                     code = CharField(max_length=10, required=True)
-                     group = CharField(max_length=10, required=True)
-                 mode = CharField(max_length=10, required=True)
+                 parent = Serializer():
+                     code = CharField(max_length=10)
+                     group = CharField(max_length=10)
+                 mode = CharField(max_length=10)
                  class Meta:
                      validators = [<NaturalKeyValidator(queryset=NaturalKeyChild.objects.all(), fields=('parent', 'mode'))>]""".replace("             ", "")[1:]  # noqa
-        self.assertEqual(str(serializer()), expect)
+        self.assertEqual(expect, str(serializer))
+
+        fields = serializer.get_fields()
+        self.assertTrue(fields['parent'].required)
+        self.assertTrue(fields['mode'].required)
+        self.assertTrue(fields['parent'].get_fields()['code'].required)
 
     def test_naturalkey_rest_post(self):
         # Posting a natural key should work
diff --git a/tests/urls.py b/tests/urls.py
index abdb29a..5e44d50 100644
--- a/tests/urls.py
+++ b/tests/urls.py
@@ -1,7 +1,6 @@
-from django.conf.urls import patterns, url, include
+from django.conf.urls import url, include
 
 
-urlpatterns = patterns(
-    '',
+urlpatterns = [
     url('', include('tests.test_app.urls')),
-)
+]