diff --git a/impl.hpp b/impl.hpp
index 15a9503..94a958e 100644
--- a/impl.hpp
+++ b/impl.hpp
@@ -20,6 +20,7 @@
     RAW,   /**< raw data */
     // Keywords needing custom decoding
     B1, /**< The keyword B1 needs to be decoded specially */
+    MB, /**< Special decoding of MB meant for Build Date */
     UD  /**< Special decoding of UD meant for UUID */
 };