All Windows Phone developer unlocks via the Chevron Labs service expired on the 11th August 2012.
Who what where how?
ChevronWP7 was a way for WindowsPhone developers to unlock their WindowsPhone legitimately to publish Applications to the Windows Market Place. Within two months, ChevronWP7 had sold 10,000 Developer-Unlock tokens.
Unfortunately, this is where they realised there was a problem.
When ChevronWP7 investigated their data, they discovered that most developers unlocked their devices for non-developmental reasons. They also found out that a few purchasers thought it was a sim-unlock service, while others thought ChevronWP7 was a hacker group providing full root access.
In April 2012, after speaking with Microsoft, ChevronWP7 came to an agreement to discontinue the Developer-Unlock service.
In June 2012, ChevronWP7 confirmed the service had been discontinued. If your phone is currently unlocked via the Chevron Labs service, your device will relock itself at next sync with the Zune desktop software.
If you moved to a paid App Hub account, you may need to re-unlock the device using the Developer Registration tool. Details how to do this are located here.
Goodbye ChevronWP7, we hardly knew you. If you have been affected by this, please let us know in the comments.