diff -uNr a/flake8/engine.py b/flake8/engine.py
--- a/flake8/engine.py	2013-02-23 06:32:11.000000000 -0800
+++ b/flake8/engine.py	2020-12-22 10:54:39.845324545 -0800
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 import re
 
-import pep8
+import pycodestyle as pep8
 
 from flake8 import __version__
 from flake8.util import OrderedSet
@@ -12,7 +12,7 @@
 def _register_extensions():
     """Register all the extensions."""
     extensions = OrderedSet()
-    extensions.add(('pep8', pep8.__version__))
+    extensions.add(('pycodestyle', pep8.__version__))
     parser_hooks = []
     options_hooks = []
     try:
diff -uNr a/setup.py b/setup.py
--- a/setup.py	2013-02-23 06:32:11.000000000 -0800
+++ b/setup.py	2020-12-22 10:54:39.853324614 -0800
@@ -33,7 +33,7 @@
     install_requires=[
         "setuptools",
         "pyflakes >= 0.6.1",
-        "pep8 >= 1.4.3",
+        "pycodestyle >= 2.0",
         "mccabe >= 0.2",
     ],
     entry_points={