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 8/31/2017 (8:00AM GMT 31/8), you will be prompted to do so at that time.
• This update has a shorter than usual amount of time before it becomes mandatory.
OS version released: rs3_release_xbox_dev_1710.170828-1900
Available: 6:00PM PDT 8/30 (1:00AM GMT 31/8)
Right-to-left language support for Arabic and Hebrew, which means you can now change your console language to select right-to-left languages in the Xbox settings menu. Arabic and Hebrew language support will be enabled for Preview Alpha 8/31 @ 1:00 AM PDT. Note there is a known issue which affects the sign-in screen when signing in with a Microsoft account e-mail address (see KNOWN ISSUES below for details).
The Pin block on Home, as well as the pins flyout in the new Guide now support 40 pins.
• The two discovery slots next to the resume tile show more relevant content, have clearer descriptions, visual improvements and we’ve given you the ability to influence what is being presented via the upvote/downvote in the context menu.
• It’s easier to see your custom background images on Home.
The Broadcast tab in the guide is redesigned and includes more info about your Mixer account including Level, Sparks, Total Views, Mixer channel pic, and more. Mixer broadcasters can now broadcast at up to 1080p. No need to change anything in settings, when you start the broadcast we automatically check your bandwidth to optimize quality.
• Active parties and broadcasting sessions are now easier to manage than ever. Similar to background audio, active party and broadcast management now show up on the Guide landing page for quicker and easier access.
• Tournaments are now easier to find via Guide under the Multiplayer tab.
• Game Hub
Going to the Game Hub for your favorite games now takes you to the new Game Hub Welcome tab. The Welcome tab features a summary of all the great content around the game in one page. See what achievements you’re closest to, which friends are playing, popular community content and more.
Navigation is clearer with new visual updates that include showing you a peek at what’s below Home, making the focus rectangle more visible in the Guide, and more.
• Fixed an issue which caused Home customizations to disappear after a console reboot.
• Fixed an issue which sometimes caused a console crash when adding or removing content blocks.
• Numerous small fixes and performance improvements for Home and the dashboard.
• Games & Apps
• Fixed issues which sometimes prevented games and apps from launching.
• Fixed an issue which sometimes prevented games and apps from transferring between hard drives.
When using Arabic or Hebrew language and signing in with a profile using the “Lock it down” security preference, the sign-in screen which requests Microsoft account e-mail address and password is distorted. This does not affect the profile if it is set to use the “Ask for my passkey” or “No barriers” security preferences.
Workaround: Set the console to use another language, sign-in, and set the profile’s security preference to “Ask for my passkey” or “No barriers”. Alternatively, you can still type in your password as normal using the virtual keyboard though the screen is distorted.
When using Hebrew language, Netflix fails to launch.
Users in Preview Alpha who do not already have the Pins block added to Home, will need to add via the bottom of the Pins flyout in the Guide.
• Movies & TV
Fast forward, rewind, and other media controls may not function.
• 4K UHD Playback
When playing 4K or UHD content, you may encounter periodic crashes or black screens. This occurs with multiple apps which support 4K and UHD content including Movies & TV and VUDU.
• Minecraft Better Together Beta
Other games fail to launch after launching the Minecraft Beta.
Workaround: This occurs if the Minecraft Beta is the first game launched after powering on the console; launch another game before Minecraft to avoid this issue. If you are stuck in this state, hard reset your console.
• Blu-Ray Player
3D Blu-Ray content plays in 2D.
• Game Hub
Game Hub isn’t accurately tracking Gamerscore and achievement unlocks for certain games.
Quelle: Xbox Insider Forum