Hello,
Our ERP (Odoo) uses the parent's message-ID in the References of an email to update the correct discussion thread, in compliance with RFC822. The "References:" field should contain the contents of the parent's "References:" field (if any) followed by the contents of the parent's "Message-ID:" field (if any).
However, we've observed an issue when recipients use iOS Mail. When we send:
Message-ID: <randomstr-openerp-res_id@hostname> References: <randomstr-openerp-res_id@hostname>
The customer's reply omits the parent's message-ID from the References:
References: <anything-but-the-parent-message-ID>
As a result, Odoo considers the response a direct email and creates a new thread instead of updating the existing one. This problem does not occur with the macOS Mail app.
Is it possible for your iOS Mail app to include the parent's message-ID in the References field to address this issue?
Thank you.