Mozilla temporarily reintroduce support for TLS 1.0/1.1, which has been disabled by default in . Support for TLS 1.0/1.1 will be reintroduced without releasing a new version of Firefox through an experimental system applied for trial implementations of new features. The reason mentioned is that due to the coronavirus pandemic, people are forced to work from home and cannot access some important government websites that still do not support TLS 1.2.
It is worth noting that in Firefox 74, to access websites via a secure communication channel, the server must support at least TLS 1.2. The disablement was carried out in accordance with IETF (Internet Engineering Task Force). The reason for dropping support for TLS 1.0/1.1 is the lack of support for modern ciphers (e.g., ECDHE and AEAD) and the requirement to support older ciphers, whose reliability at the current stage of computing development is in question (e.g., support is required for TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA, and MD5 and SHA-1 are used for integrity and authentication checks). The ability to work with outdated versions of TLS is determined by the setting security.tls.version.enable-deprecated in about:config.
Source: opennet.ru
