Hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback enhancements are disclosed for new radio (NR) unlicensed (NR-U). In the downlink control channel, two sets of identifiers (IDs) may be explicitly or implicitly signaled. The two IDs identify a current set ID and an additional set ID. Where the two IDs match, then the ACK feedback transmitted in the current ACK message will reflect the current transmissions. Otherwise, where the two IDs are different, the additional set ID identifies any previous or different ACK information that should be transmitted for prior transmissions.