At last Apple has finally released it iOS 5.1 beta 3 build 9B5141a, beta 2 was release back in December, almost a month ago. Developers can now download via OTA (Over The Air) it seems, Apple will no doubt release the general download via the iOS developer program site soon enough.

Is this new beta 3 really that exciting? Well not a lot of information has made its way online just yet, but what we do know is that it does provide improvements and bug fixes, which is the norm nowadays when a new build has been released.

This is where a lot of source code digging comes into play, we will not give out source names just yet, but apparently there could be suggestions of new devices being released such as processors of the quad-core type. We visited Mac Rumors and they have posted something very interesting by way of the new iOS 5.1 beta 3 containing new API’s.

Apparently the new API will help devs flag app content that should not be backed up, basically allowing the new API to mark directories or mark files that should not be backed up. “For NSURL objects, add the NSURLIsExcludedFromBackupKey attribute to prevent the corresponding file from being backed up.”

The source above has updated its article 3 times now with the latest mentioning that Apple will be replacing the com.apple.MobileBackup file attribute, that was introduced iOS 5.0.1 with the new API usage in iOS 5.1.

If you are a developer and downloaded the new iOS 5.1 beta 3, please do let us know what you have found?

Screenshot image above via @CDeeRON