https://www.techradar.com/news/project-santa-cruz

Update: Facebook's big developer conference came and went in early May without the Project Santa Cruz releasing into the wild, however the week didn't end without a tease for the tetherless VR headset. 

Facebook CTO Mike Schroepfer revealed that the headset is currently in the hands of third-party developers, and that the company will have "exciting updates" to share later this year.