iPhone OS 3.1.3 was the last iOS software update for iPhone 2G (the original iPhone), iPod touch 1st generation and iOS 4.2.1 was the last software update for iPhone 3G, iPod touch 2nd generation users.
If you’re feeling left out then check out whited00r. The whited00r community has recently released whited00r 5.1, which is a heavily customised version of iOS 3.1.3 that brings some of the major iOS 4 and iOS 5 features such as such as multitasking, folders, iCloud etc to iPhone 2G, iPhone 3G, first and second generation iPod touch. It doesn’t include features such as Notification Centre and the App Store. The iCloud feature is also a hacked version, which uses DropBox.
Based on the initial reports, it seems to work quite well and doesn’t seem to cause performance issues, probably because it is a heavily customised version of iOS 3.1.3 rather than an iOS 5 port.
The installation seems to be quite simple, all one needs to do is download the custom iOS firmware file from whited00r’s website and restore your iPhone and iPod touch with it.
Wired’s Charlie Sorrel warns:
It is also completely unofficial, and although I haven’t read anything bad about it, putting an entire OS of unknown origins on your phone could obviously be a security risk.
So please proceed with caution.