This message constitutes notice of a Last Call for comments on XEP-0421. Title: Anonymous unique occupant identifiers for MUCs Abstract: This specification defines a method that allows clients to identify a MUC participant across reconnects and renames. It thus prevents impersonification of anonymous users. URL: https://xmpp.org/extensions/xep-0421.html This Last Call begins today and shall end at the close of business on 2025-01-06. Please consider the following questions during this Last Call and send your feedback to the standards(a)xmpp.org discussion list: 1. Is this specification needed to fill gaps in the XMPP protocol stack or to clarify an existing protocol? 2. Does the specification solve the problem stated in the introduction and requirements? 3. Do you plan to implement this specification in your code? If not, why not? 4. Do you have any security concerns related to this specification? 5. Is the specification accurate and clearly written? Your feedback is appreciated!