On April 5, Apple acknowledged via a support document that it “will be changing the behavior of VPN On Demand for iOS devices using iOS 6.1 and later” due to a lawsuit by patent holding firm VirnetX file against Apple in November 2011. VPN technology, which stands for Virtual Private Networking, extends corporate networks securely across public networks like the Internet, allowing users to access a private network as if they were directly connected to it.
Apple originally planned to remove the 'Always' configuration option for VPN On Demand with the 'Establish if needed' option. The revised document specifically mentions Apple will not be changing the VPN behavior on "devices that have already been shipped"...