Systems, methods, and devices for communicating MPDUs having a plurality of types are described herein. One aspect of the disclosure provides a method of processing a media access control (MAC) protocol data unit (MPDU) in a wireless system. The method includes receiving the MAC protocol data unit, the MAC protocol data unit comprising an indication of a communication in accordance with a protocol version. The method further includes selecting a replay counter from one of a first and second sets of replay counters based at least in part on the indication. The method further includes processing the received MAC protocol data unit in accordance with the selected replay counter.