Apple Removes Jailbreak API From iOS 4.2

This detection API let the MDM applications in effect ask the operating system if it had been compromised. Jailbreak exploits typically change a number of operating system files, and exploit one or another low-level OS features to let users directly load their own or third-party applications.

Previously, developers had created their own series of operating system checks to detect jailbreak.

“We used it when it was available, but as an adjunct,” says Joe Owen, vice president of engineering at Sybase, which offers the Afaria device management software. “I’m not sure what motivated their removing that….I’ve not had anyone [at enterprise customer sites] talk to me about this API being present or being removed.”

In July of this year the Library of Congress deemed that jailbreaking your iPhone in order to install applications not approved by Apple and/or to unlock is legal.