AT-100 Updates & Drivers AT-75, AT-100 and AT-300 System Update Version 1.20 This is the latest operating system version for the AT-300 / AT-100 / AT-75. Please refer to the "AT-300_100_75 System Update Procedure” pdf document included in this download for the update procedure. Atelier Series USB Driver Windows 7 64bit v1.0.0 Atelier Series USB Driver Windows 7 32bit v1.0.0 Atelier Series USB Driver Mac OS 10.7 v1.0.0 Atelier Series USB Driver Mac OS 10.6 v1.0.0 Atelier Series USB Driver Mac OS 10.5 and Earlier v1.0.0