If your mom doesnt care about OS speed, apps being a little slow etc (for the most part), then the 5S is fine.
If you actually care about enough to think about iOS 10 on it (!!!), then I would suggest looking at the 6/6S.
If your mom doesnt care about OS speed, apps being a little slow etc (for the most part), then the 5S is fine.
If you actually care about enough to think about iOS 10 on it (!!!), then I would suggest looking at the 6/6S.
I have the 5s and it has iOS 9.2. Runs just fine. Not as fast as my 6s plus, but she will not be disappointed. Some people are OCD about lag, but I have not noticed this.
When I got the 5s, I was given the chance to update. It went smoothly
You don't have to update, but you will start to get app incompatibilities as time goes on and apps get updated for newer versions of iOS. My brother has a Mini 2, which has the same specs as the 5s and it has no issues with performance. I would recommend getting at least an iPhone 6 or newer though if it were me.