Danger's T-Mobile Sidekick II handheld device is <A HREF="http://news.zdnet.com/2100-9588_22-5937838.html?tag=zdnn.alert">receiving an upgrade,</A> but users may not be notified of the change before it's about to install. Some owners of the Sidekick II, which combines a cell phone, camera, instant messaging, email and Web access, have reported seeing a version 2.3 file of the device's proprietary operating system. Users aren't notified when the 5MB file begins downloading, but they are informed when it's ready to install.