My apologies that your posts in this thread never got a proper response. I am aware of an issue with adding the PiFace Digital extension via the Android app (see my post here: Piface Digital - #8 by rsiegel ) but neither of you have specifically mentioned that.
If you’re still interested in adding it, can you let me know if these errors are still blocking you two? I don’t see any issue adding this extension via iOS or Web and want to make sure I’m not looking past an issue that still remains on these platforms with this extension.