According to the IRIS documentation, once a user id is identified, at lease one license will remain (forever if I understand it correcly). The documentation says "even if the number of processes under the user ID drops back under the maximum, InterSystems IRIS continues to allocate one license unit per process for that user ID. Only when all connections by the user ID are closed and there are no more processes under the user ID does license allocation reset to one unit for that user ID." Our organization has a lot of IP addresses. We used to connect to Cache instances directly, resulting in a lot of User Ids and license units, and recently we used a firewall/reverse proxy. So license units for the User Ids made of these individual IPs are mostly not used anymore. Is there a way to purge them?   Many thanks