Apple has apparently disabled the jailbreak detection API in iOS less than six months after introducing it.

The API allowed Apple to discover if an iPhone, iPod touch or iPad has been modified so users can load and modify applications outside of Apple's iTunes-based App Store.

According to NetworkWorld, the new iOS 4.2.1 update does not include this detecting API. Apple has not commented on the report.

The new API was part of a bundle of mobile device management (MDM) APIs released in June with iOS 4.0. These APIs were available to third-party MDM applications. With the new APIs, these servers could access directly a range of features and information in iOS or on the device. But in the recently-released 4.2 version, the API intended for detecting jailbreaks has been either removed or disabled.

This detection API let the MDM applications in effect ask the operating system if it had been compromised. Jailbreaks exploit low-level OS features to let users directly load their own or third-party applications. On the otehr hand, the jailbreak weakens the otherwise strong security features of the iPhone in a way that remote exploits are far easier to accomplish.

Apple generally warns that jailbreaking voids the device's warranty and could damage the phone.

Stefan Essar, an Independent Security Consultant, has come up with a new extension tool. dubbed antid0te that is deemed to secure the jailbroken iPhone. The antid0te tool is expected to release on December 24.