[4] RFC 2244 - ACAP -- Application Configuration Access Protocol, 2021-04-11T10:25:16.000Z, 2021-04-21T09:50:14.643Z https://tools.ietf.org/html/rfc2244#page-16

[3] RFC 3028 - Sieve: A Mail Filtering Language, 2021-04-11T10:35:14.000Z, 2021-04-21T09:35:01.781Z https://tools.ietf.org/html/rfc3028#section-2.7.3

[1]

RFC 4791 - Calendaring Extensions to WebDAV (CalDAV) (2016-01-10 08:25:07 +09:00 版) https://tools.ietf.org/html/rfc4791#section-7.5

CalDAV servers are REQUIRED to support the "i;ascii-casemap" and
"i;octet" collations, as described in [RFC4790], and MAY support
other collations.

[2] RFC 5260 - Sieve Email Filtering: Date and Index Extensions (2017-05-07 22:48:17 +09:00) https://tools.ietf.org/html/rfc5260