Drupal core is dropping support for Internet Explorer 11 in Drupal 10

Drupal core is dropping support for Internet Explorer 11 in Drupal 10 (which will be released in June 2022 at the earliest). Drupal 9 will be supported until November 2023, which means that sites that want to support Internet Explorer 11 can continue using Drupal 9 until then.

Why are we dropping support for Internet Explorer 11?

• Microsoft stopped developing Internet Explorer 11 in 2015. For that reason it is significantly behind modern browsers that have continued development. Because more and more libraries are adopting the use of those features, there is a significant cost associated with maintaining Internet Explorer 11. For example, the latest major release of CKEditor has dropped support for Internet Explorer 11, which means that Drupal 10 cannot securely support both CKEditor 5 and Internet Explorer 11.
• Microsoft itself has dropped support for Internet Explorer 11 in many of its services, and the rest will drop support in mid-2021.
• Usage of Internet Explorer 11 has decreased significantly. Drupal doesn’t collect data from its end users, so we rely on data provided by other projects such as Wikimedia, WebAIM, and Statcounter. For example, in October 2019, Wikimedia had 4.4% of its traffic using Internet Explorer 11. At the same time this year the number had dropped to 1.4%. We assume that the number of Internet Explorer 11 users will continue decreasing before the release of Drupal 10.
• We consulted several accessibility organisations, and all are either planning to drop support for IE11 soon, or already actively encouraging people to stop supporting and using it.
• Supporting Internet Explorer 11 degrades the experience for everyone. We currently supply all users extra code to make Internet Explorer 11 work. This increases the request size and makes page load time slower for everyone.
• The additional requirements of Internet Explorer 11 demand additional development time that far exceeds the browser's market share. These efforts come at the expense of new features and bug fixes.

Impacts to assistive technology users

We understand that changing browsers is disproportionately inconvenient for assistive technology users. Also, WEBAim surveys show that the usage share of Internet Explorer 11 is higher among assistive tech users.

To assess how this change might impact assistive technology users, we consulted several accessibility organisations. In each case, the organizations were actively encouraging users to stop using IE11, and recommending that projects no longer support it. WebAIM stated "continued support for [Internet Explorer 11] no longer seems reasonable"

In addition, we consulted maintainers of popular design systems, and all intend to drop Internet Explorer support within a similar timeframe as Drupal, if not sooner.

What if I need to support Internet Explorer 11?

You can continue using Drupal 9 until November 2023. We recommend you encourage Internet Explorer 11 users of your sites to switch to a supported browser as soon as possible.

Would this affect Drupal 7?

No. Drupal 7 remains compatible with Internet Explorer 11. A separate announcement will be issued if that changes.