Apple has released its fourth beta version of iOS 5. Available to paid iOS developers, the release—listed as build 9A5274d—is accompanied by matching beta versions of the iOS 5 SDK, iTunes 10.5 and Apple TV Software. It is unclear what major changes, if any, may be present in the new version. iOS 5 beta 4 is available now to paid iOS developers from the iOS Dev Center.
Update: 9 to 5 Mac reports that the update can be installed on devices running iOS 5 beta 3 via the over-the-air software update feature found within the Settings app.