diff --git a/letsencrypt-auto-source/rebuild_dependencies.py b/letsencrypt-auto-source/rebuild_dependencies.py
index 07cf3d7de..ce3599897 100644
--- a/letsencrypt-auto-source/rebuild_dependencies.py
+++ b/letsencrypt-auto-source/rebuild_dependencies.py
@@ -42,10 +42,6 @@ AUTHORITATIVE_CONSTRAINTS = {
     # Too touchy to move to a new version. And will be removed soon
     # in favor of pure python parser for Apache.
     'python-augeas': '0.5.0',
-    # Package enum34 needs to be explicitly limited to Python2.x, in order to avoid
-    # certbot-auto failures on Python 3.6+ which enum34 doesn't support. See #5456.
-    # TODO: hashin seems to overwrite environment markers in dependencies. This needs to be fixed.
-    'enum34': '1.1.6 ; python_version < \'3.4\'',
     # Cryptography 2.9+ drops support for OpenSSL 1.0.1, but we still need to support it
     # for officially supported ancient distributions like RHEL 6 or Debian 8.
     'cryptography': '2.8',