According to Apple’s description, the 2.2.1 update improves the stability of Mobile Safari and also fixes an issue where “some images saved from Mail do not display correctly in the Camera Roll. To get the latest update, fire up iTunes with your iPhone plugged in and click on the “Check for Updates” button on your iPhone screen. It should then ask you if you want to download and install or just download. The 246MB update is a little hefty, but could be worth it for stability improvements.
According to ArsTechnica, 2.2.1 update messes with your iPhone’s baseband that this may affect you if you are using an unlocked iPhone(which they still trying to confirm).
Does Apple don’t even think of a major updates, that will make people forget the financial crisis? Apple we’re still waiting for the copy-and-paste to be available in your next “minor” updates!