how much more space is required to update to newest iOS

my ipad is iPad mini 2 Wi-Fi which is 16GB

which was bought in 2013

I never updated the iOS, the iOS now is 7.0.3

Two questions

1. How much more space is required to update to the newest iOS? I am worried that it will eat up a large proportional of space.

2. Would the whole performance become much slower? I remember I update my iPhone 4S before to iOS 8 and I could describe it render the phone useless, after update the phone was so lagged that I could no longer use it but sold it away.

I never thought about updating but I now find that Apple is still selling iPad mini 2 16GB on official web and claims that it's with iOS 9

Let's block ads! (Why?)

how much more space is required to update to newest iOS