Error message

• Deprecated function: Array and string offset access syntax with curly braces is deprecated in include() (line 576 of vendor/composer/ClassLoader.php).
• Notice: Undefined variable: tracking_ids in Drupal\omanpost\Controller\OmanPostController->track_trace() (line 399 of modules/omanpost/src/Controller/OmanPostController.php).
• Warning: count(): Parameter must be an array or an object that implements Countable in Drupal\omanpost\Controller\OmanPostController->track_trace() (line 399 of modules/omanpost/src/Controller/OmanPostController.php).