Isode Limited Yahoo! Yahoo! The MESSAGELIMIT extension of the Internet Message Access Protocol (RFC 3501/RFC 9051) allows servers to announce a limit on the number of messages that can be processed in a single FETCH/SEARCH/STORE/COPY/MOVE (or their UID variants), APPEND or UID EXPUNGE command. This helps servers to control resource usage when performing various IMAP operations. This helps clients to know the message limit enforced by corresponding IMAP server and avoid issuing commands that would exceed such limit.