As Marc-Andre Lemburg points out, the magic number needs to change
because we've added Unicode marshalling to the repertoire.
diff --git a/Python/import.c b/Python/import.c
index 5340054..c3f890b 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -84,7 +84,7 @@
/* XXX Perhaps the magic number should be frozen and a version field
added to the .pyc file header? */
/* New way to come up with the magic number: (YEAR-1995), MONTH, DAY */
-#define MAGIC (20121 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (50428 | ((long)'\r'<<16) | ((long)'\n'<<24))
/* See _PyImport_FixupExtension() below */
static PyObject *extensions = NULL;