Section: D.8.4 Unknown or unforeseen message type
Content: If the UE or the network receives a UPDS message with message type not defined for the UPDS or not implemented by the receiver, it shall ignore the UPDS message. NOTE: A message type not defined for the UPDS in the given direction is regarded by the receiver as a message type not defined for the UPDS, see 3GPP TS 24.007[ Mobile radio interface signalling layer 3; General Aspects ]  [11]. If the UE receives a message not compatible with the UPDS state, the UE shall ignore the UPDS message. If the network receives a message not compatible with the UPDS state, the network actions are implementation dependent.