I have a new Android 5.1.1 box here (Himedia H8 bought just last week just a few blocks from Nuvyyo’s HQ in Kanata) with the exact same issue as other’s have posted (no Leanback mode option appears). My Tablo works fine with the unit, but needs a mouse to navigate. This makes it armchair unfriendly for other users in my home.
Interestingly, the Plex Android client had the same issue in default mode, BUT has a setting toggle for TV (Leanback) mode. It would be REALLY GREAT if Nuvyyo added this same toggle setting to the Tablo Android app (just like they’ve done in the browser version). Consider this a feature request.
Make the option visibility persistent. See also I need a leanback interface toggle for Android app.