diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100644
--- a/setup.py
+++ b/setup.py
@@ -36,5 +36,8 @@ setup(name='anycall',
       author_email='scm@smurn.org',
       url='https://github.com/smurn/anycall',
       packages=['anycall'],
-      install_requires = ['twisted', 'utwist', 'bidict', 'twistit'],
+      install_requires = ['twisted>=15.0.0', 
+                          'utwist>=0.1.2', 
+                          'bidict>=0.3.1', 
+                          'twistit>=0.2.0'],
      )
Added version requirements to dependencies.