GSO (Golden State Overnight) is a delivery company that originated in California (hence the name). Several years ago, it merged with (was bought by) GLS - and GLS is already part of the app. However, tracking numbers issued by GSO work at their own site (www.gso.com), but NOT at the GLS site. Correspondingly, GSO tracking numbers don't work in the app (when I select GLS as the courier). So, is it possible to add GSO to the app? If so, and if it'd help you to have a tracking number to test it, here's one that is active as of today: WOMC4955425-5029685
Thanks!