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Waterfox has a loyal following some picked the browser because they want to continue using legacy add-ons that Firefox does not support anymore.
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The about page does highlight the branch of the browser in the case of the screenshot above, it is Waterfox Classic that was upgraded to the new version. The latest Waterfox Classic version released displays as 2019-10 on the about page already.
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Instead, it will introduce new features and options that the classic version does not support.
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While not mentioned explicitly in the blog post, it is likely that Waterfox Current won't support all the features of Waterfox Classic. Waterfox Current on the other hand will keep up "with the modern web". The core difference between the two is that Waterfox Classic will retain classic functionality but will receive bug and security fixes only. It is the "modern, feature updated branch". Waterfox Current is the second version of the browser. There are no plans to retire this branch, and is going to be actively maintainted, the same as current. The developer of Waterfox has no plans to retire this branch according to a new blog post on the Waterfox blog. The classic channel, called Waterfox Classic, is the legacy branch of the web browser that will continue to support older standards. Additionally, Waterfox will have two separate channels going forward. The next releases of Waterfox after 56.2.14 and 68.0b1 will follow the new versioning scheme already. The new versioning scheme of Waterfox is YYYY-MM-X with Y=year, M=month, and X=hotfix, whereas the old versioning scheme used X.Y.Z with X=main version release, Y=feature release, and Z=hotfix. The organization wants to release a new version of the Firefox web browser every four weeks instead of the current scheme that has a new release ready in about six weeks on average. Mozilla announced in October 2019 that it would speed up the Firefox release cycle. Waterfox continues to support (some) NPAPI plugins, comes without Telemetry, and bootstrapped add-ons.
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The Waterfox browser is based on Firefox code but there are notable difference between the two browsers.
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