Starting with version 74.0, the Firefox browser will completely drop support for the encryption protocols TLS 1.0 and TLS 1.1. At that time, the browser will prevent users from accessing websites that do not support TLS 1.2 or later by displaying a “Secure Connection Failed” error page.
As early as 2018, Mozilla and other browser manufacturers (including Google, Microsoft, and Apple) announced plans to deprecate TLS 1.0 and TLS 1.1 in 2020 to improve the security of Internet connections.
The latest encryption protocol version TLS 1.3 Final was released in 2018, and major browsers have implemented support for the new protocol. However, there are still some sites that have not migrated to the new, more secure protocols. A scan by Mozilla in mid-2019 revealed that 8,000 of the top 1 million sites do not support TLS 1.2 or higher.
In Firefox, the browser will throw a “secure connection failed” error message with the error code “SSL_ERROR_UNSUPPORTED_VERSION”, and the error cannot be bypassed (because support for TLS 1.0 and 1.1 was removed from the browser). Therefore, it is recommended that each site take the initiative to maintain and actively update to avoid the event of connection interruption.
Finally, Firefox 74.0 Stable is scheduled for release on March 10, 2020.