Huh, you're correct those apps have much longer support than I expected - but did not check :( - from free apps (though I guess Google Authenticator is backed a

Huh, you're correct those apps have much longer support than I expected - but did not check :( - from free apps (though I guess Google Authenticator is backed a small immigrant business :D ), thanks for pointing out my error, I'd fix my comment but can no longer edit things. What I was trying to say there are a _lot_ of very old smart phones in poor communities, and they're still in use. I searched craigslist in very poor parts of the US and I can find quite a few phones that are running android <= 4, and have fingerprints implying they were in use. I would guess that that end of the spectrum has many more offline only transactions. It's also a community who may not have internet access, and may not have library access, which is how people in larger cities can access the internet (from volunteering I discovered sometimes to watch porn :-/). Not intended as a correction to your comment, but just as a backup for my statement that plenty of phones still can't use TOTP apps, the cheapest phones with t-mobile are not smartphones, and the cheapest ones on amazon are not running a recent enough android, and some even run Windows OS?!?!?!