Are iPhone replacements for software issues free? iPhone 6 is not under warranty (no Apple Care+ either), but Apple Support on the phone offered a replacement phone that I pick up at the store (no mention of cost, did not ask) because of an issue with the phone that I did not cause (no physical damage). So, will this be a complimentary iPhone replacement or will it cost money like a screen repair?

Edit: It was, in the end, replaced free of charge.
It might be free. I had an iPhone 6 replaced for free just last month. The iPhone was 6 months out of warranty, no AppleCare, but was having battery problems. Apple determined the battery was defective and replaced it for free.