How Odoo Handles Email Replies

This article is work-in-progress, here is a basic description:

1. On outgoing emails from Odoo, an odoo@mydomain.com "Catch All" email address is added as the "reply to" for the email

2. Odoo periodically checks emails received to the catch all address (every 5 minutes by default)

3. When a mail is received by odoo@mydomain.com, Odoo finds the corresponding original message that was sent, using the original "message id" header, which most email programs will send in the reply.

4. The reply message is saved in the same thread as the original message, and a notification is sent to the sender of the original message so they are aware there is a reply.