nl_tokens: The version is stored as an unsigned 32 integer in network byte order . It must be version 2 or 3 .
pl_tokens: function $version ( byte ) { version = ( version << 8 ) | byte ; if ( ++ offset < 4 ) return $version ; if ( version >= 2 && version <= 3 ) { offset = 0 ; return $num ; } throw <mask> Error ( "Invalid version number " + num ) ; }