22.214.171.124.3 Reading Category List
A category list configuration data message, as specified in in section 2.2.2, is saved as an FAI message in the user's default Calendar folder. A client can read the category list, as specified in section 126.96.36.199.2, at any time.
When clients encounter unknown tags or attributes, they SHOULD ignore them, but they SHOULD also rewrite them as-is when they rewrite the category list back to the configuration data message.
All times are to be stored relative to UTC. When a category is applied to a message, as specified in section 188.8.131.52, or the user-visible properties of the category are changed (such as color or shortcut key), the client SHOULD update the lastTimeUsed attribute and, depending on whether the client separates different message types (Mail, Calendar, Contacts, Tasks, Notes, Journal), SHOULD update the appropriate time stamp attribute as specified in section 184.108.40.206.2 with the current time.
When viewing the contents of another user's folders, the client MUST try to open the other user's category list configuration data message. If the client is able to read the configuration data message from the other user's Calendar special folder, the client MUST use the other user's category list settings, including color assignments, in place of the client's settings when it displays the other user's folders.
If the client is unable to read the configuration data message from the other user's Calendar special folder (because the other user's message store is inaccessible or the client has not been granted sufficient permissions to access the special folder), the client MUST fall back to its own category list settings.