We do not have a download file for the latest version (1.2.2), but you can try downloading it from the developer's site
Download version 1.0.5 from Mac Informer
Version: 1.0.5
Date update: Apr 29, 2012
File name: korg_x50_editor_v1.0.5_633660016471710000.dmg
Size: 13.9 MB