diff --git a/lib/Db/ReaderEntity.php b/lib/Db/ReaderEntity.php
index 66eb48a..6fa301d 100644
--- a/lib/Db/ReaderEntity.php
+++ b/lib/Db/ReaderEntity.php
@@ -24,7 +24,7 @@ abstract class ReaderEntity extends Entity {
 	 *
 	 * @return string|array
 	 */
-	public function conditional_json_decode(string $el): mixed {
+	public function conditional_json_decode(string $el) {
 		/** @var array $result */
 		$result = json_decode($el);
 		if (json_last_error() === JSON_ERROR_NONE) {
diff --git a/lib/Hooks.php b/lib/Hooks.php
index cb3cd0a..a9a87d0 100644
--- a/lib/Hooks.php
+++ b/lib/Hooks.php
@@ -79,7 +79,10 @@ class Hooks {
 		$queryBuilder->executeStatement();
 	}
 
-	private static function isJson(mixed $string): bool {
+	/**
+	 * @param mixed $string
+	 */
+	private static function isJson($string): bool {
 		return is_string($string) && is_array(json_decode($string, true)) && json_last_error() == JSON_ERROR_NONE;
 	}
 }