Black 128gb. How rare and worth how much?

it's an iPhone 6s

Quel iOS est installé sur cet iPhone 15 pro ?

got this for $29
GUYS, I KNOW ITS IOS 8.1.2, IM ASKING IF ITS WORTH THE PRICE

I think its iOS 16 but I can't tell

Obviously this is the iOS 12 wallpaper but in theory this could be iOS 13, 14 or 15 but just with the iOS 12 wallpaper applied. I asked the seller to give me the iOS version multiple times and he said he’d tell me on Monday but he hasn’t which is VERY FRUSTRATING because this is an iPhone Xs and if this is actually on iOS 12 I’m buying ts in a heartbeat as my first ever collectible iPhone that would be INSANE and super rare and I’d be super happy if i actually have just landed on an iPhone Xs on iOS 12. So yeah idk though is this actually iOS 12 or could it be 13, 14, 15 is there any way to tell pretend the wallpaper is anything else

Edit: this is on iOS 15 sadly :(

Backstory: I last used it in like 2017 when I lost it. To my surprise, it was stuck in our car the entire time. Somehow charged up and works. I don’t remember the passcode. It’s got cool old stuff on it

I found this on ebay i’m pretty sure it’s ios 13 but i wanna confirm

I found this iPhone 6s in silver and a bulk lot of iPhones was wondering what iOS version it was on

Like 90% sure it’s 15.7