diff --git a/admin_manual/installation/php_configuration.rst b/admin_manual/installation/php_configuration.rst
index 6a372912b..73566a6fa 100644
--- a/admin_manual/installation/php_configuration.rst
+++ b/admin_manual/installation/php_configuration.rst
@@ -128,4 +128,4 @@ You can search for a parameter with the following command: ``grep -r date.timezo
     /etc/php/8.3/cli/php.ini
 
 .. note:: Path names have to be set in respect of the installed PHP
-          (8.1, 8.2 or 8.3) as applicable.
+          (8.1, 8.2, 8.3 or 8.4) as applicable.
diff --git a/admin_manual/installation/system_requirements.rst b/admin_manual/installation/system_requirements.rst
index c260f8442..c3093fb22 100644
--- a/admin_manual/installation/system_requirements.rst
+++ b/admin_manual/installation/system_requirements.rst
@@ -35,6 +35,7 @@ For best performance, stability and functionality we have documented some recomm
 | PHP Runtime      | - 8.1 (*deprecated*)                                                  |
 |                  | - 8.2                                                                 |
 |                  | - **8.3** (*recommended*)                                             |
+|                  | - 8.4                                                                 |
 +------------------+-----------------------------------------------------------------------+
 
 See :doc:`source_installation` for minimum PHP-modules and additional software for installing Nextcloud.
diff --git a/admin_manual/release_notes/upgrade_to_31.rst b/admin_manual/release_notes/upgrade_to_31.rst
index 474c34f38..59f9532fd 100644
--- a/admin_manual/release_notes/upgrade_to_31.rst
+++ b/admin_manual/release_notes/upgrade_to_31.rst
@@ -6,6 +6,7 @@ System requirements
 -------------------
 
 * PHP 8.1 is now deprecated but still supported.
+* PHP 8.4 is now supported, but 8.3 is recommended.
 
 PHP configuration
 -----------------
diff --git a/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst b/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst
index a05b7ab1e..29376f983 100644
--- a/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst
+++ b/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst
@@ -65,6 +65,39 @@ Removed APIs
 Back-end changes
 ----------------
 
+Support for PHP 8.4 added
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In this release support for PHP 8.4 was added. Follow the steps below to make your app compatible.
+
+1. If ``appinfo/info.xml`` has a dependency specification for PHP, increase the ``max-version`` to 8.4.
+However, it is recommended to always support all PHP versions that are compatible with supported Nextcloud version.
+In that case the ``php``-dependencies entries can be omitted.
+
+.. code-block:: xml
+
+  <dependencies>
+    <php min-version="8.1" max-version="8.4" />
+    <nextcloud min-version="29" max-version="31" />
+  </dependencies>
+
+
+2. If your app has a ``composer.json`` and the file contains the PHP restrictions from ``info.xml``, adjust it as well.
+
+.. code-block:: json
+
+  {
+    "require": {
+      "php": ">=8.1 <=8.4"
+    }
+  }
+
+3. If you have :ref:`continuous integration <app-ci>` set up, extend your test matrix with PHP 8.4 tests and linters.
+This happens automatically when you reuse our `GitHub Workflow templates <https://github.com/nextcloud/.github>`__,
+but you can also use the underlying `icewind1991/nextcloud-version-matrix Action <https://github.com/icewind1991/nextcloud-version-matrix>`__ directly.
+
+Information about code changes can be found on `php.net <https://www.php.net/migration84>`__ and `stitcher.io <https://stitcher.io/blog/new-in-php-84>`__.
+
 Added APIs
 ^^^^^^^^^^