According to implementations, a communication device receives a packet data convergence protocol (PDCP) protocol data unit (PDU) over a data radio bearer (DRB) configured for the communication device. The PDCP PDU includes an indication of a delivery mode to be used in delivering PDCP SDUs received on the DRB to an upper layer associated with the communication device, where the indication of the delivery mode indicates in-order delivery (IOD) or out-of-order delivery (OOD). The communication device processes the PDCP PDU to produce a PDCP SDU and a COUNT value associated with the PDCP SDU. The communication device delivers the PDCP SDU to the upper layer in accordance with an indication of the delivery mode.