Famously, Firefox just isn't on iOS systems. Parent company Mozilla have said that this is because of the way in which Apple forces third party developers to use certain software to build their apps, and that they previously didn't want to make any compromises for their users.
Well that seems to be changing if some tweets are to be taken seriously. During an internal Mozilla meeting on the 2nd of December, two staff members staff members tweeted about bringing Firefox to iOS.
As the second tweet states, if Mozilla wants to keep up with its user base its going to have to make the transition some time, though with the falling market share of Apple this decision might have been better made a few years ago.
As this is the first news we've heard, there's no telling when Firefox will actually appear on iOS and in what form. And this certainly doesn't count as an official announcement so we'll wait to see what the kind of feedback Mozilla provides.