Even if MikeOK has a PC and wanted to update from there, he would need the programming interface SM-PCE1. That was one of the first items I bought for my Di2 bike. I knew I didn't want to drag my bike to the LBS every time Shimano updated some part of Di2. E-Tube for the PC does not support connecting through Bluetooth.

I have not tried to use E-Tube for iOS or Android, since I do not have any of the bluetooth enabled Di2 accessories. But he wouldn't need SM-PCE1 with the Tablet and Smartphone versions.