diff --git a/rsa/__init__.py b/rsa/__init__.py
index 0b287b8..bf48834 100644
--- a/rsa/__init__.py
+++ b/rsa/__init__.py
@@ -30,7 +30,7 @@
 
 __author__ = "Sybren Stuvel, Barry Mead and Yesudeep Mangalapilly"
 __date__ = "2016-03-17"
-__version__ = '3.4'
+__version__ = '4.0-alpha'
 
 # Do doctest if we're run directly
 if __name__ == "__main__":
diff --git a/setup.py b/setup.py
index 3b41d25..a4d1d41 100755
--- a/setup.py
+++ b/setup.py
@@ -18,7 +18,7 @@
 
 if __name__ == '__main__':
     setup(name='rsa',
-          version='3.4',
+          version='4.0-alpha',
           description='Pure-Python RSA implementation',
           author='Sybren A. Stuvel',
           author_email='sybren@stuvel.eu',