Methods, systems, and devices for wireless communication for adaptive ultra-reliable low-latency communications (URLLC) semi-persistent scheduling (SPS) are described. One method includes determining a data packet payload size for a transmission using SPS resources in a transmission time interval (TTI). The method also includes sending a release signal to release a portion of the SPS resources in the TTI based on the size and transmitting the data packet during the TTI using unreleased SPS resources. Another method includes identifying that a packet profile of packets transmitted on SPS resources varies by more than a packet profile threshold and sending, based at least in part on the identifying, a request-to-update (RTU) signal to update the SPS resources. The method also include receiving a confirmation of receipt of the RTU signal and updating a resource allocation or a resource attribute based at least in part on the packet profile and confirmation of receipt.