diff --git a/patacrep/songs.py b/patacrep/songs.py
index 00c1d1b9..dd69e03b 100755
--- a/patacrep/songs.py
+++ b/patacrep/songs.py
@@ -156,6 +156,7 @@ class Song(object):
             pickle.dump(
                     cached,
                     open(cached_name(self.datadir, self.subpath), 'wb'),
+                    protocol = -1
                     )
 
     def __repr__(self):