https://www.theguardian.com/technology/2020/sep/24/arrival-of-nhs-contact-tracing-app-heralds-return-of-qr-codes > Simplicity and lack of need for physical contact make scanning QR codes the perfect solution for the app > As people across England and Wales download the long-awaited NHS contact-tracing app on Thursday, they’ll also contribute to one of the most unlikely revivals of the Covid era: the humble QR code.