How would I download apps on an unlocked iPhone 3g?

[Zack Rivers]

I just got an iPhone 3G on ebay and I got the MMS working just fine but I want to be able to use Facebook, Instagram,Twitter and all the other Social apps but everytime I try to download one it says "UPDATE REQUIRED This app requires iOS 4.3." But the iPhone is Unlocked and I am using T-Mobile so I don't want to mess it up by installing the wrong update or something /:
I am currently using iOS 4.2.1 with Baseband 06.15.00
So if anyone can post a video with a link or something that would be awesome!!! ^__^

[Rudolf Qnan]

well, You can't really do anything about it unless you update your software.
factory unlocked iPhone 3g will always be unlocked,
contact the seller on eBay and ask him if it's ok to update the unlocked ipHone3g.

first did you buy it brand new?
was it brand new?
or used?
if yes, was it factory unlocked? or or locked with at&t or verizon and the seller unlocked the phone?
was it used and the seller unlocked the phone. or if it was factory unlocked, you don't have worry about updating the software, because it won't messed up the unlocked.
I bought my iphone 3g on eBay and that was a mistake I did. because the internet on unlocked phone they said, the internet wouldn't work because it needed the software update, even I updated the software , the internet still would not work. that means i could not do any downloading apps or something.. no internet all .. so I HAD TO RETURN IT>