Earlier this month, Mozilla, Google and Microsoft announced they’re ending support for RC4 Cipher in Firefox, Google Chrome, and Microsoft Internet Explorer 11 and Edge browsers in starting on January 2016.
RC4 deprecation in Firefox 44 browser
Today Mozilla said they’re going to disable RC4 by default from Firefox 44 onwards, which was set to release on January 26. Mozilla does that by toggling a preference value to false in about: config. When that change takes place, Firefox browser won’t negotiate RC4 with Web Servers.
How to disable RC4 cipher in Firefox right now
1. Visit about: config
2. Change security.tls.unrestricted_rc4_fallback preference value to ‘false‘.