I have an iphone 11 (non pro) I use as a GPS. The update works fine on it, I haven't noticed any unusual slowdown. If I'm not mistaken, that's a 6 year-old mode

I have an iphone 11 (non pro) I use as a GPS. The update works fine on it, I haven't noticed any unusual slowdown. If I'm not mistaken, that's a 6 year-old model, and I think it's the oldest one supported. I can't comment on the battery life, since it's plugged in almost all the time. I haven't noticed any change on my regular phone (14 pro).