Which is the best iOS for iPhone 3G? I am currently on 3.1.3 !

My recommendation is to stay right where you are, do not update to iOS 4.2.1.

I second that.

I third that (if there is such a thing). 😉

My 3G is on 4.2.1 and I wish I were still on 3.1.3... folders and unified inbox are not worth the lags and general slow operation. It's not unbearable, just a bit frustrating at times. Even a restore as new didn't help much at all. Hello iP5 whenever you're released!

If I may, I agree that version 3.1.3 is the best for the iPhone 3G, however, I am currently travelling in Europe and I have a SIM card from a local mobile company. I discovered the hard way that there is an option missing: Settings > General > Network > Cellular Data (on/off). This option is not present in iOS 3.1.3. So basically, you disable 3G but it is impossible to block EDGE, and your phone will automatically revert to it if 3G is not available, and you will occur cellular data fees anyway.

I am sure of what I am saying because with the local service I use, I have unlimited data for $4 per day, but it is debited as soon as I consume one byte of data, then it is free until midnight the same day. Event if I have set Enable 3G = off, Data Roaming = off, for two days in a row, I was still charged the $4 a day because the Cellular Data was not off!

I compared with my wife's iPhone 3GS with iOS 5.1, there is the three options, Enable 3G (on/off), Data Roaming (on/off), Cellular Data (on/off). The option to turn it off simply doesn't exists on iOS 3.1.3!

With some research, I found that it is possible to block it anyway if you change your APN (Access Point Name) to an invalid setting. The easiest way to do this is to connect to the Internet using WiFi, then access this web site with Safari: http://unlockit.co.nz/ (from your iPhone).

This online tool allows you to change your APN, it is very useful when you travel abroad and you use local SIMs. On the first screen press Continue, on the second screen press Custom APN to create an APN for a local mobile company, or press Disable Data (FakeAPN) to disable 3G and Edge for good. When creating a Custom APN, you will be asked to choose a Country and a Provider, then press Create Profile. Then, either way, press Install and "Install Now" or "Replace", then press Done. This will add two things to your phone: first, an app-like icon for quick access to the website http://unlockit.co.nz/, second, a new menu in Settings > General, labelled "Profile", that contains your new APN. Note that it is possible to add several profile information, and some may conflict with each other. Remove those you don't need. Don't remove them if you are not sure!

I hope this works for you!

you can still downgrade to ios 3.1.3 with no errors

your the boss 🙂

****, even on 2016 is the same, just tried on my 3g and its the same 😀