Even that was handled badly. In my case when I went to authorized shop in central London. The guy did some test and said everything is ok and I didn't quality to change of battery (I tested using coconutBattery.app battery health was below 80% and I still was on warranty). I asked for battery replacement and pay for it out of my pocket and he also said he cannot do it because they are not allowed to change battery if their tooling said everything is ok. Had to buy 3rd party battery and replace myself.
Heh. Here in Australia, after that debacle Apple offered cheap battery replacements to anyone who wanted one for a year. I took my 3yr old iPhone 6S in and had them replace the battery. After I got it back, GPS stopped working. So I took it back in and they replaced the whole phone free of charge with a new (well factory refurbished) phone.
It was annoying coming and going to the Apple Store. But hey - replacing my 3yr old phone with a new refurb for $30? That was a great deal.
For these kind of things (common repairs that are easy (for a specialist with the right tooling) to do), you're often better going to the cheap local phone repair place rather than the official store.
You can replace the battery. You always have been able to. I did a few months later. So I don't know what you're complaining about.
But why do it before you need to? I'd vastly prefer my OS to be able to continue supporting a degraded battery before I get a chance to replace it, rather than just shut down without warning.
It did not go far enough. I discovered during a recent Internet outage that my iPhone 13 Mini will shut off at 9% if I use it as a mobile hotspot for my iPad. I had expected it to go until 0. The remaining battery capacity is at 85%.
It did for me. I had a phone that would suddenly die whenever I used it for anything too intensive, especially whenever the battery was under 40%.
The update fixed it.