+use Symfony\Component\Lock\Store\FlockStore;
+use Symfony\Component\Lock\Store\SemaphoreStore;
+
+@trigger_error(sprintf('The %s class is deprecated since Symfony 3.4 and will be removed in 4.0. Use %s or %s instead.', LockHandler::class, SemaphoreStore::class, FlockStore::class), E_USER_DEPRECATED);