A: Hello!

Yes, we support sequential invoice numbering. And we already support XRechnung starting from v2.2, and it's very stable. You can create compliant invoices and export either as ZUGFeRD (PDF+XML) or pure XML. Give it a try, if you find any issues or missing options please open a support ticket. E-invoicing is our top priority, including XRechnung, Factur-X and more, and we take it very seriously. 🙌

Check this guide: https://invoiless.tawk.help/article/xrechnung-compliance

Also, Invoiless is available in German, you can change the language from your settings.