For users considering an install of iOS 5, you may want to think twice before doing so.
AppleInsider reports that Apple has informed iOS testers that any iOS devices updated to iOS 5 beta cannot be downgraded back to iOS 4. Users who install the new firmware will only be able to upgrade to newer releases of iOS 5.
The notice was reportedly given to developers alongside the availability of the iOS 5 beta downloads. It remains to be seen if a hack can enable iOS 5 downgrading or if iOS 5 will have a jailbreak tool.