Maths calculators

So I currently have a Casio Fx- 83GT Plus model. (Works perfectly fine)
I was wondering whether I should get the latest version of the calculators as apparently they have new features? or stick to this one... I also wish to take maths for A level too.

Since you're planning on taking maths to A level I recommend this one
https://www.amazon.co.uk/Casio-FX-991ESPLUS-SA-UH-FX-991ESPLUS-Scientific-Calculator/dp/B0034BAQS8/ref=sr_1_1?ie=UTF8&qid=1476733789&sr=8-1&keywords=casio+fx-991es+plus

But for GCSE any scientific calculator should be fine