https://www.rfc-editor.org/info/rfc2060/
RFC 2060: Internet Message Access Protocol - Version 4rev1 | RFC Editor
Dec 1, 1996 - The Internet Message Access Protocol, Version 4rev1 (IMAP4rev1) allows a client to access and manipulate electronic mail messages on a server. [STANDARDS-TRACK]
access protocolrfcinternetmessageversion
https://datatracker.ietf.org/doc/html/rfc3501
RFC 3501 - INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1
INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1 (RFC 3501, ; obsoleted by RFC 9051)
access protocolrfcinternetmessageversion