Well, it's not just to be faster. 57 is also quite a bit more secure and extensions will break far less often in the future. It also means a lot less maintenanc

Well, it's not just to be faster. 57 is also quite a bit more secure and extensions will break far less often in the future. It also means a lot less maintenance work for Mozilla. It's mainly more secure by having most things sandboxed now. That requires Firefox to be executed in the new multiprocess architecture and for that they would have had to kill off at least those legacy extensions that are not multiprocess-compatible, which was essentially all of them as well. Also, yes, multiprocess did also most definitely play into performance. But we're not talking about the difference between 56 to 57, it's rather the difference between 47 to 57. Because 48 already introduced multiprocess, even though as a user you were still perfectly capable of installing a multiprocess-incompatible extension, which then caused Firefox to drop out of multiprocess whenever that extension became active. A completely intransparent way for users to completely kill off their performance. Lastly, you don't claim that what Mozilla did on a whole is wrong, but yeah, just to point it out anyways: They are somewhat throwing power users under the bus right now. They don't enjoy doing it (essentially all Mozilla devs just as well are Firefox power users), but they do want to save their market share in order to still have a word when it comes to web standards and the market share just isn't made out of power users. Around 40% of Firefox users in Sep. 2015 did not have any extensions installed. Another sizeable chunk will have their ad blocker and nothing else. This release won't affect these users negatively at all. They'll just get the better performance and the better security. The only thing I heard from my parents was my mum asking me, if it's normal that Firefox looks different now. Maybe there'll be some confusion with the new Library-button, but other than that, it's just yet another browser-UI. They know this.