[SITE-5441] Add release note for PHP security updates

src/source/releasenotes/2026-01-05-php-81-82-83-84-security-updates.md

@@ -0,0 +1,19 @@
+---
+title: "PHP 8.1, 8.2, 8.3 and 8.4 updated to their latest security patch releases"
+published_date: "2026-01-05"
+categories: [infrastructure]
+---
+_**Editorial note**: These updates were completed and deployed to the platform on December 23rd 2025._
+
+PHP versions [8.1.34](https://www.php.net/ChangeLog-8.php#8.1.34), [8.2.30](https://www.php.net/ChangeLog-8.php#8.2.30), [8.3.29](https://www.php.net/ChangeLog-8.php#8.3.29), and [8.4.16](https://www.php.net/ChangeLog-8.php#8.4.16) are now available on the platform. These updates include important security fixes, along with bug fixes and enhancements that improve performance and stability. Updates will be applied automatically over the next few days, so no manual action is required.
+
+PHP 8.4 is only available with the new [PHP Runtime Generation 2](/php-runtime-generation-2).
+
+The PHP 8.4 upgrade process automatically includes an upgrade to PHP Runtime Generation 2 if your site hasn't been upgraded already.
+
+**Important PHP version information**
+
+* PHP 8.1 and 8.2 are currently receiving security-only updates.
+* For more details, see the full list of [PHP supported versions](https://www.php.net/supported-versions.php).
+
+For the best performance and security, Pantheon recommends running PHP 8.2 and above.