diff --git a/install_minimal/upgrades/airtime-1.9.0/airtime-upgrade.php b/install_minimal/upgrades/airtime-1.9.0/airtime-upgrade.php
index 9f7813c18..a8b977fa1 100644
--- a/install_minimal/upgrades/airtime-1.9.0/airtime-upgrade.php
+++ b/install_minimal/upgrades/airtime-1.9.0/airtime-upgrade.php
@@ -8,6 +8,7 @@
 
 set_include_path(__DIR__.'/../../../airtime_mvc/library' . PATH_SEPARATOR . get_include_path());
 set_include_path(__DIR__.'/../../../airtime_mvc/library/pear' . PATH_SEPARATOR . get_include_path());
+set_include_path(__DIR__.'/../../../airtime_mvc/application/models' . PATH_SEPARATOR . get_include_path());
 require_once 'conf.php';
 require_once 'DB.php';