Mobile 'phone - 3GS to 4S
 

I have a 3G-S and in order to download a messaging application, called Whats app, it says I have to have OS 4G-S, is this possible as a downloadable software upgrade or does it mean I have to get a new 'phone please?

(I did get a 4G 'phone but the wife nicked it, I now have her old one!:{).

try to make sense of this
iPhone 3GS - Wikipedia, the free encyclopedia

I suspect that you're misreading the requirement and you need a later version of iOS4 - not 4GS which is a phone model

Correct Milo, it says I need iOS 4.3

I don't think thats available now - you'll have to install a newer version, basically whatever Apple thinks is correct

see iOS: How to update your iPhone, iPad, or iPod touch

scroll down to "update your device using iTunes" and start from there

Thanks Milo - need to be connected to my PC so will do it as soon as I get home at the WE.

back up everything before you try it
including any iTunes music......
If it goes tits-up (as it may) you'll have to restore the phone back to basic settings. I'm sure others here must have more experience than me with this upgrade

Milo
 

Worked perfectly, didn't back-up and have lost contacts, which can be rebuilt.
Took a long time, about one hour, thanks again.

EDIT: It did back-up! Just re-connected the iphone and it went straight into 'restore' mode!