Mustang version 2.5.1, released Thu, 2022-05-12, fixes minor validation issues and switches to XRechnung version 2.2, mandatory as of August 2022. (Please note that while XR 2.2 can already be written, the validation is currently only possible available up to including version 2.1.)
Additionally, Despatch Advices are first supported, in terms of a hybrid Cross Industry Despatch advice in a pilot stage and in terms of the UBL based 1Lieferschein as a proof of concept for write support only.
Please note that since version 2.5.0 it is no longer possible to use “=” in the command line version between parameters and their options, i.e. e.g. instead of “–action=validate” one has to use the previously already available “–action validate”.