What's an Ios 4.0 cause I just got a new Iphone but the apps require it

Well I got a iphone 3g or something like that but whenever I try getting some apps like instagram, facebook or tumblr it always says it needs and ios 4.0 or 4.3 and its kind of irritating -.-
The version is 3.0 tho'
so help?

IOS 4.0 is one of the latest operating systems for iPhones. Updating your phone to it will give you some access to new features and potential bug fixes. If you want to update it to the latest operating system for your phone(so you can use apps like instagram, facebook or tumblr) connect your iPhone to your computer via the usb port. When your iPhone is connected click check for updates and update it. I can't really give you specific instructions because it all depends on what itunes version you have. Hope this helps.

The iOS is the iphone operating system.iphones are basically miniature computers and like computers you need to update the software.

You need to have the iphone connected to the internet (through PC or wireless) to update the operating system.

Updating the operating system will, hopefully, improve certain aspects of how the iphone functions such as security and will allow you to use apps that you previously couldn't.

IOS 4.0 is the 4th major version of the iOS operating system that iPhones run with. You would need to upgrade that iPhone to 4.0 or greater. Oh & it does matter which iPhone you have.
If it is the 3G then it could only go up to 4.2.1, if it is the 3GS then it could go up to 5.1.1 (the latest version) & 6.0 when it is released on Wednesday.