Sony have started sending emails with activation codes for a preview of PS4 firmware 6.80. People who are part of the preview can share the activation code with up to 20 friends.
Firmware 6.80 includes the following updates:
Increased maximum Party participants from 8 to 16
Improved audio quality for voice chat
Chat transcription feature added and improved accessibility features
Improved network connectivity
Sony mention that if you are part of the preview program, you will not be able to join parties from your friends who are not part of the program, and vice versa. But you can send those preview invites to friends, or downgrade from the 6.80 preview back to your previous firmware.
As a reminder, if you are interested in joining the PS4 preview and beta program, you can register on the official playstation site here.
On the other hand, if you’re interested in hacking your PS4 (and it’s not jailbroken already), we advise to stay on as low a firmware as you possibly can.