Notifications in Theia each have codes within braces (private messenger) or brackets (email), and are generally grouped by the module to which they are associated with. Except for a single exception, a notification code usually also consists of an integer separated with a period and a string of characters (or possibly another integer) on the other side of the period. For example:

{8.requ}

Because braces are used here, this represents that this is a private message notification. The 8 specifies that the notification is related to the friendship system (look below for more information), and requ is the rest of the unique identifier; which in this case represents the act of requesting friendship.

Here are the different groups of notifications and their numerical ID, which is always the first part of the notification's identifier.

1. new items
2. new responses
3. item approvals
4. response approvals
5. item tracking status changes
6. my guestbook
7. administrative warnings
8. friendship system
9. club system
10. award system
11. quiz system
12. poll system
13. crush system
14. messenger system
15. my status system