A Cellular Internet-of Things, CloT, apparatus comprising: memory (804;806); and processing circuitry coupled to the memory (804;806) wherein to receive data in Non-Access-Stratum, NAS, protocol data units, PDUs, the processing circuitry is configured to: decode an attach request, sent from a CIoT user equipment, UE, (102;302;402;502;602) the attach request indicating a PDN type, the PDN type indicating a type of IP address; encode, for transmission to the CloT UE (102;302;402;502;602), an attach accept message; decode an attach complete message, sent from the CIoT UE (102;302;402;502;602); decode an initial UE message, the initial UE message sent from the CIoT UE (102;302;402;502;602) over a radio resource control, RRC, connection, the initial UE message including a NAS PDU, and the NAS PDU including encrypted uplink data and an indication whether acknowledgement or response is expected or not; check integrity of the NAS PDU; decrypt the encrypted uplink data from the NAS PDU; encode the decrypted uplink data for transmission to a PDN gateway, P-GW, (307;410;510;610); and release the RRC connection for the CIoT UE (102;302;402;502;602) based on the indication that no acknowledgement or response is expected. memory (804;806); and processing circuitry coupled to the memory (804;806) wherein to receive data in Non-Access-Stratum, NAS, protocol data units, PDUs, the processing circuitry is configured to: decode an attach request, sent from a CIoT user equipment, UE, (102;302;402;502;602) the attach request indicating a PDN type, the PDN type indicating a type of IP address; encode, for transmission to the CloT UE (102;302;402;502;602), an attach accept message; decode an attach complete message, sent from the CIoT UE (102;302;402;502;602); decode an initial UE message, the initial UE message sent from the CIoT UE (102;302;402;502;602) over a radio resource control, RRC, connection, the initial UE message including a NAS PDU, and the NAS PDU including encrypted uplink data and an indication whether acknowledgement or response is expected or not; check integrity of the NAS PDU; decrypt the encrypted uplink data from the NAS PDU; encode the decrypted uplink data for transmission to a PDN gateway, P-GW, (307;410;510;610); and decode an attach request, sent from a CIoT user equipment, UE, (102;302;402;502;602) the attach request indicating a PDN type, the PDN type indicating a type of IP address; encode, for transmission to the CloT UE (102;302;402;502;602), an attach accept message; decode an attach complete message, sent from the CIoT UE (102;302;402;502;602); decode an initial UE message, the initial UE message sent from the CIoT UE (102;302;402;502;602) over a radio resource control, RRC, connection, the initial UE message including a NAS PDU, and the NAS PDU including encrypted uplink data and an indication whether acknowledgement or response is expected or not; check integrity of the NAS PDU; decrypt the encrypted uplink data from the NAS PDU; encode the decrypted uplink data for transmission to a PDN gateway, P-GW, (307;410;510;610); and release the RRC connection for the CIoT UE (102;302;402;502;602) based on the indication that no acknowledgement or response is expected.