If you receive any error message like below after upgrading to Laravel 4.2, you should modify your queue config: production.ERROR: Undefined index: encrypt Add 'encrypt' => true, to config of Iron
'iron' => array(
'driver' => 'iron',
'project' => '50989cfbc3a9840017444043',
'token' => 'I8ONX3d2Ukyedwxm7oU9SWiKznP',
'queue' => 'crawler',
'encrypt' => true,
),