Current policy: <https://www.mediawiki.org/wiki/Compatibility#Browsers>
Affected components: **MediaWiki core, skins and extensions**. Wikimedia Foundation libraries like #Codex and #OOUI.
- Lighten the load of developers and quality assurance folks by removing browser support for very outdated versions of Firefox. Firefox 39 [[ https://en.wikipedia.org/wiki/Firefox_version_history#Firefox_38_through_44 | was released in July 2015 ]]. **Why Firefox 39?** It disabled insecure SSLv3 and RC4 (not yet clarified if that's of importance for Wikimedia infrastructure).
Several other reasons and technical abilities, which have been added in between 27 and 39 ([[ https://en.wikipedia.org/wiki/Firefox_version_history#Rapid_releases | release notes summaries ]]), :
- Improve the user experience by making pages load slightly faster and use less bandwidth, because we're going to send less CSS code (workarounds f.e. on [[ https://caniuse.com/flexbox | Flexbox ]]) down the wire.
- Unlock use of newer CSS features that do not have a fallback in Firefox (f.e. Flexbox, `position: sticky`[[ https://caniuse.com/css-sticky | caniuse ]]) and thus cannot be safely used today. This point is not solely dependent on removal of from basic support, but also a few other very old browsers (ex: IE9 & IE10 T293298) and platforms (Android 4.4 T290815) still to be tackled in similar tasks.
- Removal of certain remaining `-moz` prefixed properties, like `-moz-box-sizing`
- Take away maintenance-burden of writing fallback CSS for newer CSS features not supported. The effort spent in writing workarounds and addressing specific browser code is a waste of our limited resources.
[[ https://turnilo.wikimedia.org/#pageviews_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= | Turnilo (restricted) ]] **pageviews** statistics from last 30 days for Firefox:
2021-12-08: **22.7 million out of 21 billion including Firefox Mobile so about slightly above 0.1%**
These numbers are pageviews, not user numbers!
See also [[ https://analytics.wikimedia.org/dashboards/browsers/#all-sites-by-browser/browser-family-and-major-hierarchical-view | analytics.wikimedia.org ]] – showing no visible significance anymore.
I'm proposing to **move Firefox 27-38, from “Basic” category in the browser support matrix** and automatically move them to unknown support.
This would be effective in [[ https://www.mediawiki.org/wiki/MediaWiki_1.38 | MediaWiki 1.38 ]], to be released in Spring 2022, in extensions and libraries possibly effective with decision here.