Why does my old domain still show when I scan a dynamic QR Code, even I have changed my subdomain?

QR Codes that you have already printed will not show the new domain, because the QR Code has the old domain encoded. However, if you print new QR Codes the new domain will show in the QR Code. Please note that this is independent of the target URL. By using dynamic QR Codes you can always change the target URL even after printing.​