we've released v0.40.0 and follow-up hot fix v0.40.1 of OOUI library
It will rollout on the normal train tomorrow, Tuesday, 11 August.
Highlights in this release:
- Removal of Internet Explorer 8 specific code and fallbacks, largely
reducing size of CSS (~800+ lines on all icons) due to removal of PNG
fallback images, relying only on SVG icons from here on. This is going
to have a positive performance impact for all other users of the
This is in alignment with approved RFC on removing IE 8 Basic support
for MediaWiki core.. Hence, this release is a breaking release. If
you need continuous support in your environment for IE 8 you need to
stick with v0.39.3.
You can find details on additional new features, code-level, styling
and interaction design amendments, and all improvements since v0.38.0
in the full changelog.
If you have any further queries or need help dealing with breaking
changes, please let me know.
As always, interactive demos and library documentation is available
on mediawiki.org, there is comprehensive generated code-level
documentation and interactive demos and tutorials hosted on
OOUI version: 0.40.1
MediaWiki version: 1.36.0-wmf.4
Date of deployment to production: Regular train, starting Tuesday 11 August
 - https://phabricator.wikimedia.org/T248061
 - https://gerrit.wikimedia.org/g/oojs/ui/+/v0.40.1/History.md
 - https://doc.wikimedia.org/oojs-ui/master/demos/#widgets-mediawiki-vector-ltr
 - https://www.mediawiki.org/wiki/OOUI
 - https://doc.wikimedia.org/oojs-ui/master/