- Lighten the load of developers and quality assurance folks by removing browser support for very outdated versions of Firefox. Firefox 39 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 (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 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.
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 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 MediaWiki 1.38, to be released in Spring 2022, in extensions and libraries possibly effective with decision here.