Firefox 147.0.1 Released on Jan 16 is the current Release https://www.firefox.com/firefox/147.0.1/releasenotes/ The Firefox 148.o is currently being developed on the Beta channel and is currently at 148.0b5 when there can usually be nine builds of a version on Beta channel. Firefox 149.0 does exist as it is currently being developed on the more unstall Nightly channel as 149.0a1. Builds on Nightly channel can get checkins with updates twice a day so this means things can be a work in progress until fixed, finished or reverted. The Nightly channels are meant more for Testers and Developers in mind and not so much for regular Firefox users. https://www.firefox.com/download/all/ https://www.firefox.com/channel/desktop/ The Developer Edition channel is the same as Beta channel but with additional developer features.