Internet Message Access Protocol (IMAP) Capabilities 2009-03-24 2026-02-27 Expert Review Arnt Gulbrandsen, Dave Cridland NEWNAME obsolete REFERRAL ALERT BADCHARSET PARSE PERMANENTFLAGS READ-ONLY READ-WRITE TRYCREATE UIDNEXT UIDVALIDITY UNSEEN UNKNOWN-CTE UIDNOTSTICKY APPENDUID COPYUID URLMECH TOOBIG BADURL HIGHESTMODSEQ NOMODSEQ MODIFIED COMPRESSIONACTIVE CLOSED NOTSAVED BADCOMPARATOR ANNOTATE ANNOTATIONS TEMPFAIL MAXCONVERTMESSAGES MAXCONVERTPARTS NOUPDATE NOTIFICATIONOVERFLOW BADEVENT UNDEFINED-FILTER METADATA UNAVAILABLE AUTHENTICATIONFAILED AUTHORIZATIONFAILED EXPIRED PRIVACYREQUIRED CONTACTADMIN NOPERM INUSE EXPUNGEISSUED CORRUPTION SERVERBUG CLIENTBUG CANNOT LIMIT OVERQUOTA ALREADYEXISTS NONEXISTENT USEATTR DOWNGRADED MAILBOXID CAPABILITY HASCHILDREN UIDREQUIRED INPROGRESS TOOMANY TOOFEW