July 12th, 2025: We are proud to announce the immediate availability of the new version 1.7.1 of our e-invoice REST API, Mustangserver.

The release not only catches up wirh Mustangproject 2.18.0, but slightly exceeds it: one issue will only be part of the next Mustangproject release.

As mentioned in the Mustangproject announcement we now use the code already introduced in 2020 to also raise warnings in the validation of invoices which which were calculated incorrectly in a particular way. Among others, there was also a fix in the calculation of relative item allowances/charges.

With Mustangserver, you can read, write, convert and validate E-invoices. More information and the sign up for a four week evaluation period are available on the Mustangserver homepage.