For that last reason alone, you should install iOS 4.3. But there's more than just improved security in the latest upgrade: to additional apps, Safari now runs faster, iTunes Home Sharing is better integrated and personal hot spot support for the AT&T version of the iPhone has finally been rolled out.

Apple's iOS 4.3 is compatible with the iPhone 4 (the GSM model only), the iPhone 3GS, the third and fourth generations of the iPod Touch, and both the original iPad and . There's also a related AppleTV update for those who have the latest AppleTV, which was released last September. Not getting this update are the first- and second-generation iPhones, released in 2007 and 2008, and earlier versions of the iPod Touch.

In addition to the big changes offered in iOS 4.3, Apple tucked away several minor tweaks: the Camera app has a new shutter sound; the Notes app gets a few additional fonts; the Location Services setting is now prominently displayed under Settings; and Ping notifications are available.

For most users, the changes to Safari will be most obvious. Safari is now speedier, with Javascript performance twice as fast as before, according to Apple. In fact, that claim may be understated; and others who have tested the new Safari found its Nitro Engine Javascript to be noticeably faster than Apple claimed.