For info this has stopped working today for me. During the download of the OSX install media it appears the XML no longer contains the correct product ID 2019-12-12 13:21:46,024 Network Request: Fetching https://swscan.apple.com/content/catalogs/others/index-10.15-10.14-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog Product ID 041-83630 could not be found. I am assuming from looking at the file from that URL that it should contain a string for the product but it is not in there presently. Had a quick look through the code and I see that it issues the parameter via "fetch.sh" - I see on your github that a new change was committed a couple of hours ago so you probably have it in hand Edit - yep ignore me, the dockerhub was updated with the revised build to contain the new product IDs. Thank you SIO, I did a rebuild today having got some server upgrades to support this so needed to go back through and reinstall.