The 6 disc support has been rolled out. Both the disc firmware and apps will need to be on the latest versions:
Disc FW - V1.0.2.01 Build24
App - 1.01.03 (Android & iOS)
If you already had 6 discs installed prior to the updates you will need to complete the "Add Another Disc" setup from the App settings menu. This will show the extra discs in the app.