For all those with Wall Display version 1.1.1:
TL;DR: Update from the app works now, you need to first update to 1.2.1-stable, then to 2.0.0-beta2.
First, I have no idea how you managed to get that version. The first commercial production batch was with 1.1.2
Second, to update from 1.1.1 to beta, you need to pass through a intermediate update (1.2.1) to fix the update process itself. Please do so from the app - I updated the file that should be downloaded so update from the app will work now.
After you update to 1.2.1, you will be able to update to 2.0.0-beta2.