An amendment to Apple’s table in the “iPhone: Which iOS 4 software features does my iPhone support?” tech note*.

iOS 4 Feature	iPhone 3G	iPhone 3GS	Any jailbroken iPhone with Cydia
Home screen Folders	√	√	?
Unified Inbox and threading for Mail	√	√
Internet tethering	√	√	√
Multitasking		√	√
Bluetooth keyboard support		√	√
Home screen wallpaper		√	√
Data protection		√	?

* provided firmly with tonguye-in-cheek and the usual disclaimer: jailbreaking is not supported by Apple (but so are old iPhones and iPod touch models)