IMAP "$MailFlagBit" Keywords

Introduction The Internet Message Access Protocol (IMAP) specification defines the use of message keywords, and an "IMAP Keywords" registry is created in . defines a \Flagged system flag to mark a message for urgent/special attention. The new keywords defined in this document allow such a flagged message to have that flag be of one of 7 colors. This document does the following:

defines 3 new message keywords, $MailFlagBit0, $MailFlagBit1, and $MailFlagBit2, to apply to any message that has the \Flagged keyword set;
registers these $MailFlagBit0, $MailFlagBit1, and $MailFlagBit2 keywords in the "IMAP Keywords" registry;
defines which combination of these flags correspond to which colors.

Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Definition of the MailFlagBit Message Keyword The 3 flag color keywords $MailFlagBit0, $MailFlagBit1, and $MailFlagBit2 make up a bit pattern that defined the color of the flag as such:

Bit 0	Bit 1	Bit 2	Color
0	0	0	red
1	0	0	orange
0	1	0	yellow
0	1	1	green
0	0	1	blue
1	0	1	purple
0	1	1	gray

These flags SHOULD be ignored if the \Flagged system flag is not set. If the \Flagged system flag is set, the flagged status MAY be displayed to the user in the color corresponding to the combination of the 3 flag color keywords.

Implementation Notes A mail client that is aware of these flag color keywords SHOULD clear all 3 flag color keywords when the user unflags the message, i.e. when unsetting the \Flagged system flag, all 3 flag color keywords SHOULD also be unset.

IANA Considerations 3 IMAP/JMAP keywords are registered in the IMAP/JMAP keywords registry, as established in RFC5788.

IMAP/JMAP Keyword Registrations

$MailFlagBit0 keyword registration

IMAP/JMAP keyword name:: $MailFlagBit0
Purpose:: 0 bit part of a 3-bit bitmask that defines the color of the flag when the has the system flag \Flagged set
Private or Shared on a server:: SHARED
Is it an advisory keyword or may it cause an automatic action:: No
When/by whom the keyword is set/cleared:: This keyword is set by an IMAP or JMAP client as the result of a user action to "flag" a message for urgent/special attention.
Related keywords:: $MailFlagBit1, $MailFlagBit2
Related IMAP capabilities:: None
Security considerations:: None
Published specification:: This document
Intended usage:: COMMON
Owner/Change controller:: IESG

$MailFlagBit1 keyword registration

IMAP/JMAP keyword name:: $MailFlagBit1
Purpose:: 0 bit part of a 3-bit bitmask that defines the color of the flag when the has the system flag \Flagged set
Private or Shared on a server:: SHARED
Is it an advisory keyword or may it cause an automatic action:: No
When/by whom the keyword is set/cleared:: This keyword is set by an IMAP or JMAP client as the result of a user action to "flag" a message for urgent/special attention.
Related keywords:: $MailFlagBit0, $MailFlagBit2
Related IMAP capabilities:: None
Security considerations:: None
Published specification:: This document
Intended usage:: COMMON
Owner/Change controller:: IESG

$MailFlagBit2 keyword registration

IMAP/JMAP keyword name:: $MailFlagBit2
Purpose:: 0 bit part of a 3-bit bitmask that defines the color of the flag when the has the system flag \Flagged set
Private or Shared on a server:: SHARED
Is it an advisory keyword or may it cause an automatic action:: No
When/by whom the keyword is set/cleared:: This keyword is set by an IMAP or JMAP client as the result of a user action to "flag" a message for urgent/special attention.
Related keywords:: $MailFlagBit0, $MailFlagBit1
Related IMAP capabilities:: None
Security considerations:: None
Published specification:: This document
Intended usage:: COMMON
Owner/Change controller:: IESG

Security Considerations This document should not affect the security of the Internet.