I'm getting a lot of questions about iOS 4, in particular related to which devices can be upgraded. Here's the info you need.
First, availability. June 21st. Currently the only word I have on iOS 4 for the iPad is that it will appear sometime this fall.
IOS 4 will be a free update for iPhone and iPod touch (unlike previous OS updates for the iPod touch, which have been chargeable, setting users back $9.99).
iOS 4 will be compatible with the following devices:
- iPhone 3G
- iPhone 3GS
- iPhone 4
- iPod touch 2nd and 3rd-generation only
Note: How can you tell if your iPod touch is 2nd and 3rd-generation? Look for the volume control buttons on the left hand side - this feature wasn't present on the 1st generation iPod touch.
The original iPhone 2G and 1st-generation iPod touch will not be able to upgrade to iOS 4.
Note: How can you tell if your iPhone is 2G? Flip it over. The fist-generation 2G handset had a metal finish on the back with a black plastic band at the bottom. 3G and 3GS handsets come in a smooth glass black or white finish.
Also, not all features will be available across all devices. The following features are only available for iPhone 4, iPhone 3GS, and the 3rd-generation iPod touch:
- Custom wallpaper
- Bluetooth keyboard support
More info on iOS 4 here.