diff --git a/README.md b/README.md
index 3b6fb0f..b9cfbf8 100644
--- a/README.md
+++ b/README.md
@@ -45,7 +45,7 @@ from within a virtual environment (e.g., via [virtualenv](https://pypi.org/proje
 
 ## Requirements
 
-* Python 3.1 or higher 
+* Python 3.5 or higher 
 
 ## Getting started
 
diff --git a/setup.py b/setup.py
index a8363de..7eb4672 100755
--- a/setup.py
+++ b/setup.py
@@ -56,6 +56,6 @@ See http://propka.org/ for the PROPKA web server.
             ],
         },
       zip_safe=True,
-      python_requires='>=3',
+      python_requires='>=3.5',
       test_suite="tests",
 )