Monday, October 19th, 2026

On the occasion of this year’s ZUGFeRD developer days, we are published Quba 2.0 already Thursday last week, 15 October 2026.

Quba 2, the open source offline e-invoice viewer, now also supports offline validation of electronic invoices, the creation of Factur-X/ZUGFeRD files, if a PDF/A basis file is present, and is now based directly on Mustangproject.

Our Mustang/Quba ecosystem requires open-sorce contributions. For non-developers who want to contribute nevertheless, we now offer and encourage sponsorship.

Thanks to our first sponsor, Matthäi Bauunternehmen GmbH und Co KG, who enabled us to publish Quba 2 already this year.

We need more sponsors, however, as we are approaching 100,000 downloads for Quba (99,141 as of last count, with ~500 downloads per week). The majority being for the Windows platform with an additional silver sponsor we could start digitally signing our Windows installer, which makes the software a tad easier to get.

Please report issues here despite the source code for 2.0 has temporarily moved.