I feel like millions of dollars of R&D should mean it’s no longer Improvised ;)

I get that you're joking, but from the headline i assumed that they did mean physically unsafe - we all know lithium batteries have not 100% ideal failure modes, and I'm sure there are people on HN who remember the swelling laptop debacle of a few years (a decade?) back.

Disappointed that the article is actually about security, and then makes a bunch of trivially falsifiable claims, but then also it says the best time to buy an iPhone is when they're brand new and just released to maximize update range. I'm really just not sure what the point of the article actually is? Yes a just released phone is going to be getting updates further in the future than one released a year ago, but that's true for literally everything iOS, android, hell, I can't get a replacement for the bowl in my rice cooker but I can for the next model.

Quite true...though "thermal runaway fire hazard" would be the correct descriptive. (Outside of old car batteries building up hydrogen gas, "explode" is a miserably over-hyped word for dangerous non-electrical battery failures.)

OTOH - if (say) you're keeping an old phone for "emergency use only", then it's unsafe when the battery or electronics get too flaky to be relied upon for that.

Is there a time limit? I'm still using the original iPod touch as a white noise machine.