alt Hacker NewsWhat is the issue with receiving tickets as PDF? It is the most flexible yet digital option. PDFs work regardless of the medium. You can show it in the phone or you can always add them to DB Navigator App anyways or if you would like to be old school, just print them.
How about NFC? App with a QR code displayed?
Could be a force of habit for UK but that's mostly how we do tickets. Printing is usually still an option.