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Pantheon Release Notes

PHP 8.4 now available via PHP Runtime Generation 2

InfrastructureNew feature
July 15, 2025

Support for PHP 8.4 is now available on the platform with the new PHP Runtime Generation 2. PHP 8.4 is the latest version of the server-side language powering Drupal and WordPress.

CMS support

PHP 8.4 is recommended for sites running Drupal 10.4+ or 11.1+. See the Drupal PHP requirements documentation for more details.

WordPress 6.7+ only has "beta support" for PHP 8.4, therefore Pantheon does not recommend using WordPress in a production environment with this PHP version yet.

Pantheon currently recommends at least PHP 8.2 for all production sites.

New features

PHP 8.4 is not expected to bring new performance gains for sites. But for developers looking to take advantage of the latest PHP functionalities, a few new updates are notable:

  • Property Hooks: Introduces support for computed properties, allowing for pre/post-processing of values.
  • Asymmetric Visibility: Provides independent control over property read/write scope.
  • Enhanced DOM API: Adds new classes for HTML5 parsing.
  • New Array Functions: Introduces array_find(), array_find_key(), array_any(), and array_all().
  • PDO Driver Subclasses: PDO now includes driver-specific subclasses.
  • Updated JIT: Includes a new implementation of the Just-In-Time compiler.
  • Expanded String Functions: New mb_trim(), mb_ltrim(), mb_rtrim(), mb_ucfirst(), and mb_lcfirst() functions.

See the PHP 8.4 release announcement from php.net for full details.

How to upgrade

PHP 8.4 is only available with the new PHP Runtime Generation 2. To upgrade your site, set the following in your pantheon.yml file:

pantheon.yml
php_runtime_generation: 2
php_version: 8.4
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