diff --git a/setup.py b/setup.py
index 24d7134..3fa7933 100644
--- a/setup.py
+++ b/setup.py
@@ -6,9 +6,9 @@ module1 = Extension('py3dutil', sources = ['py3dutil.c', 'obarr.c', 'red_black_t
 
 buildno = 0
 if os.path.exists('buildno'):
-	buildno = load(open('buildno', 'rb'))
+	buildno = load(open('buildno', 'r'))['build']
 	buildno += 1
-dump(buildno, open('buildno', 'wb'))
+dump({'build': buildno}, open('buildno', 'w'))
 
 setup (name = 'py3dutil',
 	version = '0.3.%.4d' % (buildno,),