diff --git a/common/djangoapps/course_modes/migrations/0013_auto_20200115_2022.py b/common/djangoapps/course_modes/migrations/0013_auto_20200115_2022.py
new file mode 100644
index 0000000000..bd33c71d01
--- /dev/null
+++ b/common/djangoapps/course_modes/migrations/0013_auto_20200115_2022.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.27 on 2020-01-15 20:22
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('course_modes', '0012_historicalcoursemode'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='coursemode',
+            name='course',
+            field=models.ForeignKey(db_constraint=False, on_delete=django.db.models.deletion.DO_NOTHING, related_name='modes', to='course_overviews.CourseOverview'),
+        ),
+    ]
diff --git a/common/djangoapps/course_modes/models.py b/common/djangoapps/course_modes/models.py
index 540145d711..e2aca1b2c5 100644
--- a/common/djangoapps/course_modes/models.py
+++ b/common/djangoapps/course_modes/models.py
@@ -54,7 +54,7 @@ class CourseMode(models.Model):
         db_constraint=False,
         db_index=True,
         related_name='modes',
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
     )
 
     # Django sets the `course_id` property in __init__ with the value from the database
diff --git a/common/djangoapps/course_modes/tests/test_models.py b/common/djangoapps/course_modes/tests/test_models.py
index 117ba30032..199dcdb4b2 100644
--- a/common/djangoapps/course_modes/tests/test_models.py
+++ b/common/djangoapps/course_modes/tests/test_models.py
@@ -21,6 +21,7 @@ from six.moves import zip
 from course_modes.helpers import enrollment_mode_display
 from course_modes.models import CourseMode, Mode, get_cosmetic_display_price, invalidate_course_mode_cache
 from course_modes.tests.factories import CourseModeFactory
+from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
@@ -523,6 +524,19 @@ class CourseModeModelTest(TestCase):
         self.assertEqual(CourseMode.is_masters_only(self.course_key), expected_is_masters_only)
 
 
+class TestCourseOverviewIntegration(ModuleStoreTestCase):
+    def test_course_overview_version_update(self):
+        course = CourseFactory.create()
+        course_overview = CourseOverview.get_from_id(course.id)
+        course_overview.version -= 1
+        course_overview.save()
+        course_mode = CourseModeFactory.create(course_id=course_overview.id)
+
+        assert CourseMode.objects.filter(pk=course_mode.pk).exists()
+        CourseOverview.get_from_id(course.id)
+        assert CourseMode.objects.filter(pk=course_mode.pk).exists()
+
+
 class TestDisplayPrices(ModuleStoreTestCase):
     @override_settings(PAID_COURSE_REGISTRATION_CURRENCY=["USD", "$"])
     def test_get_cosmetic_display_price(self):
diff --git a/common/djangoapps/entitlements/migrations/0014_auto_20200115_2022.py b/common/djangoapps/entitlements/migrations/0014_auto_20200115_2022.py
new file mode 100644
index 0000000000..f7fa755e30
--- /dev/null
+++ b/common/djangoapps/entitlements/migrations/0014_auto_20200115_2022.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.27 on 2020-01-15 20:22
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('entitlements', '0013_historicalcourseentitlementsupportdetail'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='courseentitlementsupportdetail',
+            name='unenrolled_run',
+            field=models.ForeignKey(blank=True, db_constraint=False, null=True, on_delete=django.db.models.deletion.DO_NOTHING, to='course_overviews.CourseOverview'),
+        ),
+    ]
diff --git a/common/djangoapps/entitlements/models.py b/common/djangoapps/entitlements/models.py
index 9efe7bb432..f018d3e0ba 100644
--- a/common/djangoapps/entitlements/models.py
+++ b/common/djangoapps/entitlements/models.py
@@ -499,7 +499,7 @@ class CourseEntitlementSupportDetail(TimeStampedModel):
         null=True,
         blank=True,
         db_constraint=False,
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
     )
 
     history = HistoricalRecords()
diff --git a/openedx/core/djangoapps/content/course_overviews/models.py b/openedx/core/djangoapps/content/course_overviews/models.py
index 568394eaa2..e32f8068e1 100644
--- a/openedx/core/djangoapps/content/course_overviews/models.py
+++ b/openedx/core/djangoapps/content/course_overviews/models.py
@@ -321,9 +321,8 @@ class CourseOverview(TimeStampedModel):
         try:
             course_overview = cls.objects.select_related('image_set').get(id=course_id)
             if course_overview.version < cls.VERSION:
-                # Throw away old versions of CourseOverview, as they might contain stale data.
-                course_overview.delete()
-                course_overview = None
+                # Reload the overview from the modulestore to update the version
+                course_overview = cls.load_from_module_store(course_id)
         except cls.DoesNotExist:
             course_overview = None