Mandatory.
Specify the ID of the message.
Rules

• For new messages, the Message ID must not be the same as any other message ID in the message file.
• Maximum length is 7 characters.

Tips & Techniques

• Standards should be defined for all message IDs. For example, message IDs are generally in the format or AAA9999 where AAA identifies a group of messages and 9999 is a sequence number within the group.