Enhancement of feature support after interworking

A User Equipment (UE), comprising:

• a Protocol data unit (PDU) session handling circuit that maintains a PDU session in a 5G system (5GS) of a mobile communication network, wherein the UE supports a local IP address in Traffic Flow Template (TFT) feature;
• a mobility management circuit that converts the PDU session in 5GS to a packet data network (PDN) connection upon switching from 5GS to an evolves packet system (EPS), wherein the UE assumes the network supports the local IP address in TFT feature for the PDN connection;
• a receiver that receives a modify EPS bearer context request or a activate dedicated EPS bearer context request message carrying a TFT information element (IE) from the network, wherein the TFT IE carries a TFT operation code and includes a local IP address;
• and
• a controller that executes the TFT operation code including the local IP address without diagnosing an error.