What is TLS?
TLS (short for Transportation Layer Security) is a cryptographic protocol used to establish a secure communications channel between two systems. It is used to authenticate one or both systems, and protect the confidentiality and integrity of information that passes between systems.
Here are the browsers that do not support TLS 1.2:
Chrome version 29 and older
Firefox version 26 and older
Internet Explorer version 10 and older
Safari 6 and older