Version 1.8.0 of Mustangserver was released 18 December 2025, and supported ZUGFeRD 2.4 as well as styledinvoices, a way to exert full visual control on created Factur-X invoices.
Today, February 6th, 2026, we already released the subsequent version 1.8.1, which ships with a calculate endpoint, enabling e.g. invoice creation forms to easily obtain live previews of taxes and total amounts for users.