Answer is under construction 👷...
I'll check with our Beta group to find out what the "oldest" successful verified OS are, but we don't recommend being too far out-of-date. Glitches are much more likely the older back you go.
- Android KitKat (v4.4.x): Chrome and any browser based on the Android KitKat Chromium engine probably does not work. A very late point-releases of KitKat (v4.4.6 maybe) might work. However, using Firefox or Opera might work. I will be testing the latter two and updating this post.
- Android Jellybean (v4.2.x): Likely works if you can install a recent version of mobile Chrome (v63). e.g., Asus memo pad 10 me102a tablet w/Android 4.2.2, Chrome 63.
- Amazon FireOS Lollipop (v18.104.22.168): Silk works. Older versions might be compatible with if you side-load Chrome. Testers have claimed good success with "Fully Kiosk browser".
- iOS: Absolute minimum version not yet determined. v9.2 works, but Safari may have a glitch with color bulbs, currently being investigated.
- iPad 1: ActionTiles is incompatible with iPad Generation 1.
- Android: Incompatible with Dolphin browser.
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