Abstract from the RFC text:
This document extends IMAP (RFC 3501) SEARCH and UID SEARCH commands with several result options, which can control what kind of information is returned. The following result options are defined: minimal value, maximal value, all found messages, and number of found messages.
Notes: None
There are no errata for RFC 4731 (as of 2008-08-25).
Used in the following classes: