From: Billing <billing@supplier.example>
To: jane@example.org
Subject: Urgent: invoice 2026-0915 overdue
Importance: high
Date: Thu, 10 Sep 2026 08:00:00 +0000
Message-ID: <inv-20260915@supplier.example>
Content-Type: text/plain; charset="utf-8"

Dear customer,

Invoice 2026-0915 is now overdue. Please arrange payment at your
earliest convenience.

Supplier Accounts