Discussion: Dropping support for IE11

After digging into data and reviewing previous decisions around browser support, this is a proposal to define a policy to stop supporting Internet Explorer 11 (IE11) now that usage has cumulatively fallen below ~1% across three metrics. 

Current state of IE11

As of February 25th 2021, IE11 usage has cumulatively fallen below ~1% according to three sources of metrics:

  • 0.71% from StatCounter’s GlobalStats.
  • 1.2% from W3 Counter.
  • 0.46% from WordPress.comWordPress.com An online implementation of WordPress code that lets you immediately access a new WordPress environment to publish your content. WordPress.com is a private company owned by Automattic that hosts the largest multisite in the world. This is arguably the best place to start blogging if you have never touched WordPress before. https://wordpress.com/.

For comparison, the numbers above are very close to the data used to make a decision in 2017 to drop support for IE versions 8, 9, and 10. It’s important to keep in mind that when viewing these statistics in the context of WordPress, these percentages represent tens (if not hundreds) of thousands of users that could potentially be left behind if support for IE11 is dropped. 

In August 2020 Microsoft themselves announced that Microsoft 365 and Teams apps would stop supporting IE in the upcoming months. However, given that IE11 is a component bundled with Windows10, according to the IE Lifecycle it will still receive security updates as long as the Windows version it was shipped with continues to receive support. 

In terms of the current WordPress user experience, a flag was added to not recommend IE in BrowseHappy about 13 months ago, so by now, most WordPress users should be aware. Tied to this, the experience overall is not optimal in IE11 with a high cost of maintenance for developers.

Proposed Policy

The proposed policy for WordPress is to end Internet Explorer 11 support. This was discussed most recently in the February 24th Core Editor Chat and briefly during February 23rd JavaScript office hours in SlackSlack Slack is a Collaborative Group Chat Platform https://slack.com/. The WordPress community has its own Slack Channel at https://make.wordpress.org/chat/.. More context and discussion have been shared over time in this original Trac issue that seeks to determine clear guidelines around what absolutely can’t be broken in order to help identify development and testing needs. 


Dropping support would result in smaller scripts, lower maintenance burden, and decrease build times. For instance, a recent exploration by @youknowriad demonstrated that not transpiling the scripts to IE11 immediately resulted in a net reduction of nearly 84kB in the GutenbergGutenberg The Gutenberg project is the new Editor Interface for WordPress. The editor improves the process and experience of creating new content, making writing rich content much simpler. It uses ‘blocks’ to add richness rather than shortcodes, custom HTML etc. https://wordpress.org/gutenberg/ JavaScriptJavaScript JavaScript or JS is an object-oriented computer programming language commonly used to create interactive effects within web browsers. WordPress makes extensive use of JS for a better user experience. While PHP is executed on the server, JS executes within a user’s browser. https://www.javascript.com/. built files, representing a 7,78% total decrease in size; these scripts have seen a size contraction up to 60%, with an average reduction of 24%. This is a result of heavily relying on transpilers, further explained by Jason Miller, Web DevRel at Google. Moreover, dropping support would ultimately make WordPress’ currently included polyfill script obsolete, decreasing the enqueued scripts size up to 102kB more.

The smaller downloads would positively impact all users, especially those on slower networks, or computing devices. We expect a result of dropping IE11 support to improve performance for the vast majority of users. 

Potential Concerns/Blockers

TLDR: The concerns are for those who are unable to upgrade, like financial institutions and education sectors, and those who rely on IE11 for screen readers. 

There are major institutions like banking, government, and education that are unable to control when they can upgrade sometimes due to legal requirements, depending on the country. This further underscores the need to determine a policy that takes into consideration both a data-informed approach and the impacted user bases while weighing the potential benefits for the wider web. 

According to a September 2019 WebAIM survey, IE11 is still used as a browser among screen readers with 11.5% share. This is an older survey and IE11’s global share was 2.9% at the time the survey was done according to the sources linked above. It takes time for screen reader software to support newer browsers and the latest versions of popular screen reader NVDA have continued improving and adding support for the Edge browser. As a result, this post embraces an assumption that IE usage among screen reader users has declined since the survey as the software improves and overall usage of IE11 has declined. Please let us know if this assumption is or if there is better data available to refer to.

Keep in mind that there are ways to patchpatch A special text file that describes changes to code, by identifying the files and lines which are added, removed, and altered. It may also be referred to as a diff. A patch can be applied to a codebase for testing. gaps in functionality that’s determined critical to maintain for a time. This post does not seek to go into technical implementation details though.

Share your feedback about this proposed policy change to drop support by March 18th

This is a tough decision to make and we want to solicit feedback from as many voices across the community it may impact. Please note, this post is not meant to go over any technical fallbacks at this time but to purely discuss the policy of dropping support. 

Once we’ve gathered feedback, the next step will be to consolidate and decide the policy. The actual technical implementation of the policy is most practical to pursue across the numerous WordPress projects. 

Thank you to @mkaz, @annezazu, @youknowriad, @desrosj for help writing and reviewing this post. 

#accessibility, #browser-support, #performance