diff --git a/extlib/megahal.py b/extlib/megahal.py
index cd42b6b..a4a0df6 100644
--- a/extlib/megahal.py
+++ b/extlib/megahal.py
@@ -136,7 +136,7 @@ class Brain(object):
 
     def __init__(self, order, file, timeout):
         self.timeout = timeout
-        self.db = shelve.open(file, writeback=True)
+        self.db = shelve.open(file, protocol=2, writeback=True)
         if self.db.setdefault('api', API_VERSION) != API_VERSION:
             raise ValueError('This brain has an incompatible api version: %d != %d' % (self.db['api'], API_VERSION))
         if self.db.setdefault('order', order) != order: