RFC 6154, "IMAP LIST Extension for Special-Use Mailboxes", March 2011Source of RFC: morg (app)
Errata ID: 5265
Reported By: Roy A. Gilmore
Date Reported: 2018-02-25
Throughout the document, when it says:
In RFC6154, the special-use attributes are consistently shown with initial capitals, but there doesn't appear to be any guidance whether the special-use attributes are case-sensitive, case-insensitive, or implementation defined. This could lead to interoperability issues.