Mustangproject is an open source e-invoicing library and toolkit.
It helps companies to process electronic invoices by providing the functionality to read, write and validate them.

New in version 2

Instead of ZUGFeRD 1, ZUGFeRD version 2 is now the default choice and the library is now available via Maven Central, making it even easier to embed. It’s interface has been enhanced and Mustangproject now supports absolute and relative charges and allowances on item and document level and embedding additional files.

The validator component, which had been developed separately under the project name “ZUV”, has now been merged into
the mainline project and development will be continued there.
It allows the automatic syntactical and arithmetical check of electronic ZUGFeRD 1 and 2 as well as XRechnung 2 invoices.

So far, Mustangproject supported the e-invoice standards Factur-X/ZUGFeRD 2.1, the new release adds support for version 2.1.1 with the
ZUGFeRD “reference profile” XRechnung, as well as a native XRechnung export.

Mustangproject 2.0 will be published on 2020-11-12 between 16:00 and 17:00 CET on it’s Homepage and Maven Central.
Until then, the current alpha-3 prerelease can be tested. Further details of the upcoming release can be obtained from it’s release notes.