It's been exactly two weeks since Apple rolled iOS 6.1 beta 3 out to registered developers, but those with the software installed needn't worry about it having it go stale on their phones. MacRumors notes that Apple today made the fourth beta of iOS 6.1 available to developers, pushing it out over the air and also making it available for download from the official developer website. The new iOS 6.1 beta features the build number 10B5126b. Beta 4 is compatible with the iPhone 5, iPhone 4S, iPhone 4, iPhone 3GS, iPad mini, third and fourth generation iPads, iPad 2 and the fourth and fifth generation iPod touch models.
Apple has been releasing beta versions of iOS 6.1 since the start of November, and so far some of the changes include a new Reset Advertising Identifier and a new pass in the Passbook app to better introduce the app to new users. There's no word yet on what new features, if any, Apple has packed into iOS 6.1 beta 4, but I'm sure that devs will begin digging into it shortly. It's also unclear when us regular folk will get to take iOS 6.1 for a spin, but hey, at least it looks like Apple is making progress with the next version of iOS 6. If you're a registered iOS developer, head on over to the dev site or go into Settings > General > Software Update and get your beta on.