diff --git a/CHANGELOG.md b/CHANGELOG.md
index 693a0a7..e9fbc15 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 Changelog for FormIt.
 
+# FormIt 5.2.5
+
+- Fix HTTP 500 on PHP 8.4 when AJAX config hits session/cache (#308).
+- Store only scalar snippet properties in session/cache.
+
 # FormIt 5.2.4
 
 - Fix saving ajaxToken in POST fields.
diff --git a/_build/gpm.yml b/_build/gpm.yml
index d655879..f2edff1 100644
--- a/_build/gpm.yml
+++ b/_build/gpm.yml
@@ -3,7 +3,7 @@ lowCaseName: formit
 description: FormIt is a dynamic form processing Snippet for MODx Revolution. It handles a form after submission, performing validation and followup actions like sending an email. It does not generate the form, but it can repopulate it if it fails validation.
 author: Sterc
 namespace: Sterc\FormIt
-version: 5.2.4
+version: 5.2.5
 
 build:
   setupOptions: "setup.options.php"
diff --git a/core/components/formit/src/FormIt/Request.php b/core/components/formit/src/FormIt/Request.php
index 92b5294..e1b6af4 100644
--- a/core/components/formit/src/FormIt/Request.php
+++ b/core/components/formit/src/FormIt/Request.php
@@ -141,8 +141,8 @@ public function prepare()
 
         /* if not a form submission, store config for AJAX handling */
         if (!$this->hasSubmission()) {
-            $properties = $this->config;
-            $properties['pageId'] = $this->modx->resource ? $this->modx->resource->get('id') : null;
+            $properties = $this->getStorableAjaxConfig($this->config);
+            $properties['pageId'] = $this->modx->resource ? (int) $this->modx->resource->get('id') : null;
 
             $ajaxToken = bin2hex(random_bytes(16));
 
@@ -238,6 +238,20 @@ public function runRenderHooks()
         $this->formit->renderHooks->loadMultiple($this->config['renderHooks'], $fields, array(), $errors);
     }
 
+    /**
+     * Keep only scalar values that can be stored in session and MODX file cache.
+     *
+     * @param array<string|int, mixed> $config
+     *
+     * @return array<string|int, mixed>
+     */
+    private function getStorableAjaxConfig(array $config): array
+    {
+        return array_filter($config, static function ($value) {
+            return $value === null || is_scalar($value);
+        });
+    }
+
     /**
      * Checks to see if a POST submission for this form has occurred
      *