diff --git a/classes/privacy/provider.php b/classes/privacy/provider.php
index 8ca80c8..a9eb79e 100644
--- a/classes/privacy/provider.php
+++ b/classes/privacy/provider.php
@@ -67,7 +67,7 @@ public static function _get_metadata(collection $collection) {
      */
     public static function _export_user_preferences($userid) {
 
-        $raw = (array) json_decode(get_user_preferences('editor_marklar/formats', null, $userid) ?? '');
+        $raw = (array) json_decode(get_user_preferences('editor_marklar/formats', '', $userid));
 
         if (is_array($raw)) {
             foreach ($raw as $format => $enabled) {
diff --git a/lib.php b/lib.php
index 2e78cb5..ed7265a 100644
--- a/lib.php
+++ b/lib.php
@@ -58,7 +58,7 @@ public function get_supported_formats() {
         $supported = [FORMAT_MARKDOWN => FORMAT_MARKDOWN];
 
         // Other formats can be supported via user preferences.
-        $formats = json_decode(get_user_preferences('editor_marklar/formats') ?? '');
+        $formats = json_decode(get_user_preferences('editor_marklar/formats', ''));
 
         if (is_object($formats)) {
             if (!empty($formats->{'format'.FORMAT_MOODLE})) {
diff --git a/preferences.php b/preferences.php
index 6fa0554..c8eea6f 100644
--- a/preferences.php
+++ b/preferences.php
@@ -41,7 +41,7 @@
     'monospace' => get_user_preferences('editor_marklar/monospace', false, $user),
 ];
 
-$formats = json_decode(get_user_preferences('editor_marklar/formats', null, $user) ?? '');
+$formats = json_decode(get_user_preferences('editor_marklar/formats', '', $user));
 if (is_object($formats)) {
     $data = array_merge($data, (array)$formats);
 }