diff --git a/.travis.yml b/.travis.yml
index 9a625a1..b96fb60 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,9 +2,11 @@ language: python
 
 matrix:
   include:
+    - { python: "3.6", env: DJANGO=2.1 }
     - { python: "3.6", env: DJANGO=2.2 }
     - { python: "3.6", env: DJANGO=3.0 }
 
+    - { python: "3.7", env: DJANGO=2.1 }
     - { python: "3.7", env: DJANGO=2.2 }
     - { python: "3.7", env: DJANGO=3.0 }
 
diff --git a/computedfields/resolver.py b/computedfields/resolver.py
index ac1f825..5eae0f0 100644
--- a/computedfields/resolver.py
+++ b/computedfields/resolver.py
@@ -8,6 +8,7 @@
 import logging
 import pickle
 
+import django
 from django.db import transaction
 from django.db.models import QuerySet
 from django.conf import settings
@@ -68,7 +69,7 @@ def __init__(self):
         self._fk_map = {}
         self._local_mro = {}
         self._m2m = {}
-        self._batchsize = getattr(settings, 'COMPUTEDFIELDS_BATCHSIZE', 100)
+        self._batchsize = getattr(settings, 'COMPUTEDFIELDS_BATCHSIZE', 100 if django.VERSION >= (2,2) else 0)
 
         # some internal states
         self._sealed = False        # initial boot phase
@@ -615,11 +616,15 @@ def bulk_updater(self, queryset, update_fields, return_pks=False, local_only=Fal
                         setattr(elem, comp_field, new_value)
                 if has_changed:
                     change.append(elem)
-                if len(change) >= self._batchsize:
+                if self._batchsize and len(change) >= self._batchsize:
                     model.objects.bulk_update(change, fields)
                     change = []
             if change:
-                model.objects.bulk_update(change, fields)
+                if self._batchsize:
+                    model.objects.bulk_update(change, fields)
+                else:
+                    for elem in change:
+                        elem.save(update_fields=fields, skip_computedfields=True)
 
         # trigger dependent comp field updates on all records
         # skip recursive call if queryset is empty
diff --git a/example/test_full/tests/test_m2m_advanced.py b/example/test_full/tests/test_m2m_advanced.py
index b46a634..f992c5e 100644
--- a/example/test_full/tests/test_m2m_advanced.py
+++ b/example/test_full/tests/test_m2m_advanced.py
@@ -1,3 +1,4 @@
+import django
 from django.test import TestCase
 from ..models import Person, Group, Membership
 from django.test.utils import CaptureQueriesContext
@@ -9,8 +10,14 @@ class SelfDeps(TestCase):
     def setUp(self):
         self.persons = [Person.objects.create(name='P{}'.format(i)) for i in range(10)]
         self.groups = [Group.objects.create(name=g) for g in 'ABCDEFGHJI']
-        self.persons[0].groups.add(self.groups[0], self.groups[1])
-        self.persons[1].groups.add(self.groups[0], self.groups[1])
+        if django.VERSION >= (2,2):
+            self.persons[0].groups.add(self.groups[0], self.groups[1])
+            self.persons[1].groups.add(self.groups[0], self.groups[1])
+        else:
+            Membership.objects.create(person=self.persons[0], group=self.groups[0])
+            Membership.objects.create(person=self.persons[0], group=self.groups[1])
+            Membership.objects.create(person=self.persons[1], group=self.groups[0])
+            Membership.objects.create(person=self.persons[1], group=self.groups[1])
 
     def test_init(self):
         p0 = self.persons[0]
@@ -28,11 +35,19 @@ def test_change_group_name(self):
         self.assertEqual(p0.my_groups, 'A,b')
     
     def test_add_group(self):
-        Group.objects.create(name='Z').members.set([self.persons[0]])
+        if django.VERSION >= (2, 2):
+            Group.objects.create(name='Z').members.set([self.persons[0]])
+        else:
+            group = Group.objects.create(name='Z')
+            Membership.objects.create(group=group, person=self.persons[0])
         p0 = self.persons[0]
         p0.refresh_from_db()
         self.assertEqual(p0.my_groups, 'A,B,Z')
-        p0.groups.create(name='X')
+        if django.VERSION >= (2, 2):
+            p0.groups.create(name='X')
+        else:
+            group = Group.objects.create(name='X')
+            Membership.objects.create(group=group, person=p0)
         p0.refresh_from_db()
         self.assertEqual(p0.my_groups, 'A,B,Z,X')
 
@@ -50,11 +65,19 @@ def test_change_person_name(self):
         self.assertEqual(g0.my_members, 'P0,Px')
 
     def test_add_person(self):
-        Person.objects.create(name='Py').groups.set([self.groups[0]])
+        if django.VERSION >= (2, 2):
+            Person.objects.create(name='Py').groups.set([self.groups[0]])
+        else:
+            person = Person.objects.create(name='Py')
+            Membership.objects.create(person=person, group=self.groups[0])
         g0 = self.groups[0]
         g0.refresh_from_db()
         self.assertEqual(g0.my_members, 'P0,P1,Py')
-        g0.members.create(name='Pz')
+        if django.VERSION >= (2, 2):
+            g0.members.create(name='Pz')
+        else:
+            person = Person.objects.create(name='Pz')
+            Membership.objects.create(group=g0, person=person)
         g0.refresh_from_db()
         self.assertEqual(g0.my_members, 'P0,P1,Py,Pz')