OT: Authorize.net and TLS 1.2
Owing to new PCI DSS requirements, e-commerce sites that use Authorize.net should be aware that TLS 1.0 and 1.1 are being disabled by June 30, 2018.
Transport Layer Security (TLS), is a technology used to encrypt sensitive information sent via the Internet. TLS is the replacement for Secure Sockets Layer (SSL).
Contact your web developer or payment solution provider, as well as your web hosting company, to confirm that they can support TLS 1.2 for your API connections.
Note: If you are not using the current version of your web browser, please take a few moments to upgrade it now. Browsers released prior to 2014 may not support TLS 1.2. You can check your browser's TLS support by visiting https://www.howsmyssl.com/

