To the small subset of users in Delta that already had 1710 builds you are receiving a new 1710 build at 2.00pm PDT today
https://forums.xbox.com/en-us/thread...1-f83e8ecb11ec

HOW TO GET IT:
• If your console is in Instant-On mode and you have been selected to receive the update, it will download and install the update and reboot to standby.
NOTE: Once the update is available to you, you can manually begin the update by launching the Guide and navigating to All Settings > System > Updates.
• If your console hasn’t downloaded and installed the update by 1:00 AM PDT 10/12/2017 (8:00AM GMT 12/10), you will be prompted to do so at that time.
NOTE: This update has a shorter than usual amount of time before it becomes mandatory.

DETAILS:
OS version released: rs3_release_xbox_dev_1710.171009-1720
Available: 2:00PM PDT 10/11 (9:00PM GMT 11/10)

NEW FEATURES:

• Copy and Move Content with Ease
We've made it significantly easier to copy and transfer games/apps between external hard drives! All you need to do is follow these simple steps: 1. Navigate to Settings > System > Storage.
2. Select a connected hard drive. 3. Use the "Transfer" option to move content between hard drives. Using this feature you can move games and apps one at a time or in bulk using the "Select all" option.

• Avatars on Home
See your friends represented as avatars on your Home. New blocks you’ve added, callouts for games friends are playing, and more on your Home screen will now feature today’s animated avatars.
NOTE: After gathering some great feedback, we’re going to take a little more time to test and refine the experience for the redesigned, new Xbox avatars. We’re eager to hear about your new experiences testing the placement of today’s avatars on the Home screen. We’ll take your feedback to heart as we continue working on the redesigned, new Xbox avatars, and keep you updated on the roll out.

• Never Miss Out!
You’re here to play, but sometimes have to step away from your Xbox. We’ve enhanced the notification system when your Xbox is idle so that time-sensitive activities are visible from far away. Whether you’re still in the room or taking the dog out for a walk, your Xbox will keep you instantly up-to-date. At a glance, you’ll know if your friends have come online while you were away or if you’ve been invited to play. You’ll never miss out on what’s going on with your friends, clubs, broadcasts, and more.

We’ve also updated the screen-dimming functionality to better prevent screen ghosting, both when the screen is dimmed and when it’s showing enhanced notifications.

• Backup Settings
Streamline setup on a new console by backing up your account and key system settings to an external games & apps storage device. Plug the storage device in your new console before setting up to transfer your backed up settings. To access these features, open the Guide and navigate to System > Settings > System > Backup & transfer.

FIXES:

Since the last Preview Delta (Small) update the Xbox Team has been hard at work on hundreds of fixes and improvements which have been released to the Preview Alpha and Preview Beta audiences. If interested, you can find the full list of fixes by update in the Xbox Preview Announcements forum.

KNOWN ISSUES:

• Tournaments
• The left and right navigation for selecting date and time during Tournament creation is currently reversed when the console language is set to Arabic or Hebrew.
• Left and right navigation in Tournament twists is reversed when the console language is set to Arabic or Hebrew.
• Left and right navigation in the bracket view of Tournaments is reversed when the console language is set to Arabic or Hebrew.

• Netflix
When using Hebrew language, Netflix fails to launch. A fix for this issue will be available soon.

• Avatars on Home
Users wishing to represent themselves as an avatar can do so by changing their settings under My profile > Customize profile > Show my avatar.

Source: Xbox One Insiders - October 11th: Preview Delta (Small) build available (1710.171009-1720) : xboxone