Hey all,
Starting in January 2016, MediaWiki will end JavaScript support for Microsoft Internet Explorer 8. This raises the cut-off up from MSIE 7. Users with this browser will still be able to browse, edit, and otherwise contribute to the site. However, some features will not be available to them. For example, the enhanced edit toolbar will not appear, and the notification buttons will take you to a page rather than a pop-out.
This change will affect roughly 0.89% of all traffic to Wikimedia wikis (as of October 2015). For comparison, 0.33% of traffic comes from Internet Explorer 6, and 1.46% from Internet Explorer 7. Support for these was dropped in August and September 2014 respectively.
Providing JavaScript for IE 8 adds a significant maintenance burden. It also bloats the software we ship to all users, without proportionate benefit. This enables us to simplify and streamline the JavaScript codebase for all other users. Users unable to upgrade from Internet Explorer 8 will have a faster experience going forward, based on well-tested and more stable code.
This change will land in the development branch in January, and so will be part of MediaWiki 1.27 (to be released around May 2016).
Yours, -- Krinkle
For details about the JavaScript-less experience, see https://www.mediawiki.org/wiki/Compatibility