diff --git a/achievements.api.php b/achievements.api.php
index d9169f9..65a8ac1 100644
--- a/achievements.api.php
+++ b/achievements.api.php
@@ -155,7 +155,7 @@ function example_comment_insert($comment) {
  */
 function example_node_insert($node) {
   // Sometimes, we don't need any storage at all.
-  if (format_date(REQUEST_TIME, 'custom', 'D') == 'Mon') {
+  if (\Drupal::service('date.formatter')->format(REQUEST_TIME, 'custom', 'D') == 'Mon') {
     achievements_unlocked('node-mondays', $node->uid);
   }
 }
diff --git a/achievements.module b/achievements.module
index 4d6bd5c..e873834 100644
--- a/achievements.module
+++ b/achievements.module
@@ -234,7 +234,7 @@ function achievements_template_shared_variables(&$variables) {
   ];
   $variables['unlocked_date'] = [
     '#markup' => isset($variables['unlock']['timestamp'])
-      ? format_date($variables['unlock']['timestamp'], 'custom', 'Y/m/d')
+      ? \Drupal::service('date.formatter')->format($variables['unlock']['timestamp'], 'custom', 'Y/m/d')
       : '',
   ];
   $variables['unlocked_rank'] = [