Firefox 52 will be the company’s next Extended Support Release (ESR) branch of their popular web browser. After this release, Mozilla is planning a few changes that will break compatibility, especially if you’re building the browser from source. If you’re an end-user, the major one to look out for is Mozilla disabling NPAPI-based plugins (except Flash) unless you are using Firefox 52 ESR. This change will land in the consumer version of Firefox 52, though. It’s not really clear why they didn’t just wait until Firefox 53, rather than add a soft-kill in Firefox 52 and hard-code it the next version, but that’s their decision. It really does not affect me in the slightest.
The more interesting change, however, is that Mozilla will begin requiring Rust (and LLVM) in an upcoming version. I’ve seen multiple sources claim Firefox 53, Firefox 54, and Firefox 55 as possible targets for this, but, at some point around those versions, critical components of the browser will be written in Rust. As more of the browser is migrated to this language, it should be progressively faster and more secure, as this language is designed to enforce memory safety and task concurrency.
Firefox 52 is expected in March.