Yesterday, the Xbox team explained that several new features would roll out to Xbox Insiders later this month including a new Party overlay, Arena and Xbox Live and more. Following this announcement, the team has also released a new preview build for Preview Alpha members to kick off the gradual rollout of these new features.
— Brad Rossetti (@WorkWombatman) April 17, 2017
Please note that the following changelog doesn't reveal which new features are included in this build:
OS version released: rs2_release_xbox_1705.170411-1700
Available: 6:00PM PDT 4/17 (1:00AM GMT 18/4)
Welcome to 1705 on Xbox One! This month we’re rolling out a new party overlay, more fan-requested improvements, and later this month…Killer Instinct and World of Tanks tournaments powered by Arena on Xbox Live!
You can read more about the features coming in this update on the Xbox News Wire.
NOTE: Not all planned features for this update are available at this time
Overall, it's been a busy past couple of weeks for the Xbox team: the Xbox One March Update rolled out to everyone in late March, followed by a new feature update just last week. And as you can see, this first 1705 preview build suggests that all the new features announced yesterday should be ready for everyone in May.