It works with OpenHAB 3 … if you use latest (beta) Version 0.9.27pre of HABPanelViewer linked in first post of this topic: HABPanelViewer 0.9.26
Export your settings, uninstall Store version of that app and then you can install debug version.
There has been an incompatible change in REST interface of OpenHAB, thus requiring a new version.