iOS 7 has been jailbroken by iOS developer and jailbreak community member Ryan Petrich as is evident from his tweet on Sunday evening. The screenshot is that of an iPod touch running iOS 7. Petrich has a number of popular jailbreak tweaks to his name including Activator and LiveClock. In the latest tweet the iOS developer hasn’t put forward any explanation apart from an image showing his Activator jailbreak tweak installed on iPod touch indicating that the device has been jailbroken.
There is very less likelihood that Petrich will release the jailbreak out in the open while iOS 7 is still in its developer release cycles as he like any other jailbreaker would want to keep Apple from discovering and patching the holes he has discovered.