diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100644
--- a/setup.py
+++ b/setup.py
@@ -71,14 +71,14 @@ if __name__ == '__main__':
                 'sphinx',
             ],
             'tests': [
-                'flake8',
-                'pytest',
-                'pytest-cache',
-                'pytest-cov',
-                'pytest-flakes',
-                'pytest-pep8',
-                'freezegun',
-                'sphinx',
+                'flake8>=3.7.7',
+                'pytest>=4.3.1',
+                'pytest-cache>=1.0',
+                'pytest-cov>=2.6.1',
+                'pytest-flakes>=4.0.0',
+                'pytest-pep8>=1.0.6',
+                'freezegun>=0.3.11',
+                'sphinx>=1.8.5',
             ],
         },
         classifiers=[
updated requirements to fix readthedocs