diff --git a/setup.py b/setup.py
index 5dfa765..4a7daa9 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@ from setuptools import setup, find_packages
 
 
 here = os.path.abspath(os.path.dirname(__file__))
-execfile(os.path.join(here, 'rattail_tempmon_demo', '_version.py'))
+exec(open(os.path.join(here, 'rattail_tempmon_demo', '_version.py')).read())
 README = open(os.path.join(here, 'README.rst')).read()