Microsoft made a new system software update for the Xbox One available to preview members, numbered xb_rel_1508-150806-2200.
Below you can read the patch notes, courtesy of Program Manager Emily Hanson and posted on the private preview forums:
OS version released: xb_rel_1508-150806-2200
Available: 6:00PM PT 8/8 (2AM GMT 9/8)
A fix for notifications not appearing correctly in some locales.
A fix to address the Party Chat app force-closing in certain situations.
As usual, if you’re not part of the preview program, but would like to be, you can mention it in the comments (including your gamertag), and another reader might be able to send you an invite.
Just remember that this is a beta testing program, so you understand and accept the responsibility for any issues caused to your console, since preview members do it to make the launch of each patch smoother for everyone else, and not just to get a sneak peek on future updates.