diff --git a/py_gen/templates/oxm.py b/py_gen/templates/oxm.py
index 792c277..50eb4bd 100644
--- a/py_gen/templates/oxm.py
+++ b/py_gen/templates/oxm.py
@@ -67,18 +67,18 @@
         if ${m.name} != None:
             self.${m.name} = ${m.name}
         else:
-            self.${m.name} = ${py_gen.oftype.gen_init_expr(m.oftype)}
+            self.${m.name} = ${py_gen.oftype.gen_init_expr(m.oftype, version=version)}
 :: #endfor
 
     def pack(self):
         packed = []
-:: include("_pack.py", ofclass=ofclass)
+:: include("_pack.py", ofclass=ofclass, version=version)
         return ''.join(packed)
 
     @staticmethod
     def unpack(buf):
         obj = ${ofclass.pyname}()
-:: include("_unpack.py", ofclass=ofclass)
+:: include("_unpack.py", ofclass=ofclass, version=version)
         return obj
 
     def __eq__(self, other):