According to a report from French website
iPhoneSoft, many owners of older generations of iPhone and iPad can collectively breathe a sigh of relief. There's enough indication out there that Apple is going to support pretty much any device that was able to receive the last major upgrade to iOS 13. This means that if you happen to be holding on to your iPhone 6S, 6S Plus, or iPhone SE, you'll be able to enjoy at least one more major iOS upgrade. Considering these are devices released in the 2015-2016 timeframe, it's a blessing that Android users can only dream of even on the high-end side.
The story is a bit different if you own an iPad Mini 4 or iPad Air 2, which use slower A8 and A8x processors, which apparently won't make the cut. In the case of iPod touch, you'll only get the next iOS upgrade as long as you have the latest version that launched last year.