Hi, thank you for the responses. Sikorka looks definitely interesting and I have been keeping new eye on but I don’t think it is ready on mainnet yet. Even when they become available, it is android only solution so I have to have fallback plan for people who don’t have iPhone nor even smart phone. Unlike games or other shopping app, meetup checkup process have to be inclusive for various people. The lowest tech approach is just ask people to bring the printout of qr code I think.