Should I update my iphone 4S to iOS 8.1?

[Ari]

I've just 'upgraded' to an iphone 4S! (I know I know... )

It's telling me that there's a software upgrade to 8.1 available (it's running 7.1.2 at the mo).

Worth upgrading or is that really for the newer machines?

[Ari]

Hmmm... mixed views then.

What do I actually stand to gain with 8.1?