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.
RFC 4731-2006 history
2006RFC 4731-2006 IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned