Twenty Twenty-One, Twenty Twenty, and Twenty Seventeen updates now available

New versions for the Twenty Twenty-One, Twenty Twenty, and Twenty Seventeen default themes are now available for download. If your site has enabled auto-updates for these themes, you should be receiving the updates shortly. The new versions are as follows:

  • Twenty Seventeen: 3.5
  • Twenty Twenty: 2.5
  • Twenty Twenty-One: 2.1

These updates revert a recent change from using false !== strpos( ... ) in favor of the newer native str_contains() PHPPHP The web scripting language in which WordPress is primarily architected. WordPress requires PHP 5.6.20 or higher function made in [55988], and released in coordination with WordPress 6.3 in August 2023.

While this is a desirable change overall, str_contains() is only available in PHP >= 8.0. To help modernize the code base, a polyfill was merged into WordPress CoreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. in [52039] and first released as a part of WordPress 5.9. Because all three of these themes work with versions of WordPress earlier than 5.9, any site running WordPress < 5.9 could run into fatal PHP errors.

To find more information on this change, check out #60241 on TracTrac An open source project by Edgewall Software that serves as a bug tracker and project management tool for WordPress..

Special thanks goes out to all of the contributors that helped with this release.

Aaron Jorbin, Carolina Poena, Sergey Biryukov and Stephen Bernhardt.

Props @jeffpaul for pre-publication review.