diff --git a/setup.py b/setup.py
index 629e059..1f5c686 100644
--- a/setup.py
+++ b/setup.py
@@ -21,9 +21,10 @@
 DEPENDENCIES = (
     "cachetools>=2.0.0,<5.0",
     "pyasn1-modules>=0.2.1",
-    # rsa >= 4.1 no longer supports python 2 https://github.com/sybrenstuvel/python-rsa/issues/152
-    'rsa<4.1; python_version < "3"',
-    'rsa>=3.1.4,<5; python_version >= "3"',
+    # rsa==4.5 is the last version to support 2.7
+    # https://github.com/sybrenstuvel/python-rsa/issues/152#issuecomment-643470233
+    'rsa<4.6; python_version < "3.5"',
+    'rsa>=3.1.4,<5; python_version >= "3.5"',
     "setuptools>=40.3.0",
     "six>=1.9.0",
 )