diff --git a/.travis.yml b/.travis.yml
index 946f8ba..6ce7124 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,24 +1,16 @@
 language: python
 sudo: false
 python:
-- "2.7"
-- "3.6"
+- "3.7"
+- "3.8"
+- "3.9"
 env:
   global:
   - PYTHONPATH=tests/testapp
   matrix:
-  - DJANGO_VERSION=">=1.8,<1.9"
-  - DJANGO_VERSION=">=1.9,<1.10"
-  - DJANGO_VERSION=">=1.10,<1.11"
-  - DJANGO_VERSION=">=1.11,<2.0"
-  - DJANGO_VERSION=">=2.0,<2.1"
-  - DJANGO_VERSION=">=2.1,<2.2"
-matrix:
-  exclude:
-  - python: "2.7"
-    env: DJANGO_VERSION=">=2.0,<2.1"
-  - python: "2.7"
-    env: DJANGO_VERSION=">=2.1,<2.2"
+  - DJANGO_VERSION=">=2.2,<3.0"
+  - DJANGO_VERSION=">=3.1,<3.2"
+  - DJANGO_VERSION=">=3.2,<4.0"
 install:
 - travis_retry pip install codecov
 - travis_retry pip install -U -r dev-requirements.txt
diff --git a/nplusone/ext/django/middleware.py b/nplusone/ext/django/middleware.py
index 1027b9a..01c36fb 100644
--- a/nplusone/ext/django/middleware.py
+++ b/nplusone/ext/django/middleware.py
@@ -7,10 +7,7 @@
 
 from django.conf import settings
 
-try:
-    from django.utils.deprecation import MiddlewareMixin
-except ImportError:
-    MiddlewareMixin = object
+from django.utils.deprecation import MiddlewareMixin
 
 from nplusone.core import listeners
 from nplusone.core import notifiers
diff --git a/nplusone/ext/django/patch.py b/nplusone/ext/django/patch.py
index fa8b5fb..cd7db13 100644
--- a/nplusone/ext/django/patch.py
+++ b/nplusone/ext/django/patch.py
@@ -6,26 +6,17 @@
 import importlib
 import threading
 
-import django
 from django.db.models import query
 from django.db.models import Model
 
 from nplusone.core import signals
 
-if django.VERSION >= (1, 9):  # pragma: no cover
-    from django.db.models.fields.related_descriptors import (
-        ReverseOneToOneDescriptor,
-        ForwardManyToOneDescriptor,
-        create_reverse_many_to_one_manager,
-        create_forward_many_to_many_manager,
-    )
-else:  # pragma: no cover
-    from django.db.models.fields.related import (
-        SingleRelatedObjectDescriptor as ReverseOneToOneDescriptor,
-        ReverseSingleRelatedObjectDescriptor as ForwardManyToOneDescriptor,
-        create_foreign_related_manager as create_reverse_many_to_one_manager,
-        create_many_related_manager as create_forward_many_to_many_manager,
-    )
+from django.db.models.fields.related_descriptors import (
+    ReverseOneToOneDescriptor,
+    ForwardManyToOneDescriptor,
+    create_reverse_many_to_one_manager,
+    create_forward_many_to_many_manager,
+)
 
 
 def get_worker():
@@ -88,16 +79,8 @@ def get_related_name(model):
 
 def parse_field(field):
     return (
-        (
-            field.related_model  # Django >= 1.8
-            if hasattr(field, 'related_model')
-            else field.related_field.model  # Django <= 1.8
-        ),
-        (
-            field.remote_field.name  # Django >= 1.8
-            if hasattr(field, 'remote_field')
-            else field.rel.related_name  # Django <= 1.8
-        ) or get_related_name(field.related_model),
+        field.related_model,
+        field.remote_field.name or get_related_name(field.related_model),
     )
 
 
@@ -142,11 +125,7 @@ def parse_many_related_queryset(args, kwargs, context):
     rel = context['rel']
     manager = context['args'][0]
     model = manager.instance.__class__
-    related_model = (
-        manager.target_field.related_model  # Django >= 1.8
-        if hasattr(manager.target_field, 'related_model')
-        else manager.target_field.related_field.model  # Django <= 1.8
-    )
+    related_model = manager.target_field.related_model
     field = manager.prefetch_cache_name if rel.related_name else None
     return (
         model,
diff --git a/nplusone/ext/sqlalchemy.py b/nplusone/ext/sqlalchemy.py
index f69514a..ca132b4 100644
--- a/nplusone/ext/sqlalchemy.py
+++ b/nplusone/ext/sqlalchemy.py
@@ -15,13 +15,13 @@
 
 def to_key(instance):
     model = type(instance)
-    return ':'.join(
-        [model.__name__] +
-        [
+    return ':'.join(itertools.chain(
+        [model.__name__],
+        (
             format(instance.__dict__.get(key.key))  # Avoid recursion on __get__
             for key in get_primary_keys(model)
-        ]
-    )
+        )
+    ))
 
 
 def get_primary_keys(model):
diff --git a/setup.cfg b/setup.cfg
index c4dc8b0..138c91f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -9,6 +9,7 @@ universal=1
 # E265: block comment should start with #
 # E301: expected 1 blank line, found 1
 # E302: expected 2 blank lines, found 0
+# W504: line break after binary operator
 [flake8]
-ignore = E127,E128,E265,E301,E302,E305,E306
+ignore = E127,E128,E265,E301,E302,E305,E306,W504
 max-line-length = 90
diff --git a/tox.ini b/tox.ini
index bdabbd3..ea74851 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist={py27,py33,py34,py35,py36}-{django18,django19,django110,django111,django20,django21}
+envlist={py37,py38,py39}-{django22,django31,django32}
 
 [testenv]
 deps=
@@ -19,12 +19,9 @@ deps=
     peewee
 
     ; Django versions
-    django18: django>=1.8,<1.9
-    django19: django>=1.9,<1.10
-    django110: django>=1.10,<1.11
-    django111: django>=1.11,<2.0
-    django20: django>=2.0,<2.1
-    django21: django>=2.1,<2.2
+    django22: django>=2.2,<3.0
+    django31: django>=3.1,<3.2
+    django32: django>=3.2,<4.0
 commands=
     flake8 .
     py.test