diff --git a/model_utils/fields.py b/model_utils/fields.py
index a349b7c..f308706 100644
--- a/model_utils/fields.py
+++ b/model_utils/fields.py
@@ -228,7 +228,7 @@ class SplitField(models.TextField):
         return value.content
 
     def value_to_string(self, obj):
-        value = self._get_val_from_obj(obj)
+        value = self.value_from_object(obj)
         return value.content
 
     def get_prep_value(self, value):
diff --git a/model_utils/managers.py b/model_utils/managers.py
index 3e345c9..6558bf9 100644
--- a/model_utils/managers.py
+++ b/model_utils/managers.py
@@ -139,10 +139,10 @@ class InheritanceQuerySetMixin(object):
         if levels:
             levels -= 1
         while parent_link is not None:
-            if django.VERSION < (1, 8):
-                related = parent_link.related
-            else:
+            if django.VERSION < (1, 9):
                 related = parent_link.rel
+            else:
+                related = parent_link.remote_field
             ancestry.insert(0, related.get_accessor_name())
             if levels or levels is None:
                 if django.VERSION < (1, 8):
diff --git a/model_utils/tests/models.py b/model_utils/tests/models.py
index 7bc8012..8043c9f 100644
--- a/model_utils/tests/models.py
+++ b/model_utils/tests/models.py
@@ -28,9 +28,12 @@ class InheritanceManagerTestParent(models.Model):
     # FileField is just a handy descriptor-using field. Refs #6.
     non_related_field_using_descriptor = models.FileField(upload_to="test")
     related = models.ForeignKey(
-        InheritanceManagerTestRelated, related_name="imtests", null=True)
+        InheritanceManagerTestRelated, related_name="imtests", null=True,
+        on_delete=models.CASCADE)
     normal_field = models.TextField()
-    related_self = models.OneToOneField("self", related_name="imtests_self", null=True)
+    related_self = models.OneToOneField(
+        "self", related_name="imtests_self", null=True,
+        on_delete=models.CASCADE)
     objects = InheritanceManager()
 
     def __unicode__(self):
@@ -65,7 +68,7 @@ class InheritanceManagerTestChild2(InheritanceManagerTestParent):
 class InheritanceManagerTestChild3(InheritanceManagerTestParent):
     parent_ptr = models.OneToOneField(
         InheritanceManagerTestParent, related_name='manual_onetoone',
-        parent_link=True)
+        parent_link=True, on_delete=models.CASCADE)
 
 
 class TimeStamp(TimeStampedModel):
@@ -219,7 +222,7 @@ class Tracked(models.Model):
 
 
 class TrackedFK(models.Model):
-    fk = models.ForeignKey('Tracked')
+    fk = models.ForeignKey('Tracked', on_delete=models.CASCADE)
 
     tracker = FieldTracker()
     custom_tracker = FieldTracker(fields=['fk_id'])
@@ -275,7 +278,7 @@ class ModelTracked(models.Model):
 
 
 class ModelTrackedFK(models.Model):
-    fk = models.ForeignKey('ModelTracked')
+    fk = models.ForeignKey('ModelTracked', on_delete=models.CASCADE)
 
     tracker = ModelTracker()
     custom_tracker = ModelTracker(fields=['fk_id'])