Internet Explorer 11 (IE11) was released over 7 years ago and is currently used by less than 1% of all users on the Internet with usage rapidly declining. A large majority of popular websites have already stopped supporting IE11 (including Microsoft Teams in 2020), and even the Microsoft 365 apps and services will be dropping support later this year.
When WordPress 5.8 is released in July of this year, Internet Explorer 11 will no longer be supported.
If you are currently using IE11, it is strongly recommended that you switch to a more modern browser, such as Google Chrome, Mozilla Firefox, Safari, or Microsoft Edge. IE11 users have been shown a warning that IE11 is considered outdated in the WordPress dashboard for the last 17+ months.
If you are already using one of the more modern browsers above, you will only be positively impacted by this change, as there are performance benefits to dropping IE11 support. However, if any other users of your site are still using IE11, it’s possible they will be affected.
What does “dropping support” mean?
When support for a browser is removed from WordPress, new features are no longer tested on those browsers and are not guaranteed to function optimally.
Automated tools that generate parts of the WordPress Core source code are also updated to exclude unsupported browsers. This means that any feature relying on these generated files will likely have bugs or stop working for users of those browsers.
The block editor will be the area of WordPress most heavily impacted by this change because almost all of the files related to the block editor are compiled using these automated tools. Other areas of the WordPress dashboard also use CSS built with these tools and their appearance will potentially be impacted when using IE11.
All other areas of the code base that are IE11 specific will need to be identified, evaluated, and removed on a case-by-case basis as the rest are manually maintained. This process will begin in the WordPress 5.9 release, and will likely happen gradually over several major releases. Additionally, any bugs which are reported for IE11 will not be fixed.
How will this affect themes?
No changes will be made to any of the default bundled themes as a result of this plan. No code related to IE11 support (or any other browser that may have been supported when each theme was released) will be removed from default themes. However, any new features added going forward will not be tested in IE11.
If you are not using a default theme, it’s still unlikely that your theme will be affected by this change. Themes typically have their own browser support policies, and changes in WordPress Core do not affect those. It’s possible that your theme author may have removed support for IE11 already.
If IE11 support is important to you and you are unsure whether your theme supports IE11, it is recommended that you reach out to your theme’s developer to confirm.
More information on this change can be found on the Making WordPress Core blog.