After a long period of testing, Microsoft is rolling out the first major update of 2019 to the Xbox One system, which is version 1904 and now known as the April 2019 Xbox Update. The news in this release is the same as what we've seen in the Insider rings for the past few months.
This includes a new floating on-screen keyboard that pops up next to the text input box you're typing in, which is much smaller than the previous version of the keyboard. You can still enable the larger keyboard in the settings if you need it for accessibility reasons.
Microsoft is also making improvements to Xbox Game Pass Quests, making it possible to see your progress from the Game Pass dashboard as well as bringing all of your quests to the My Profile page.
There are some quality-of-life updates in this release as well, including a new restart option in the Power Center, allowing you to more quickly reboot the system without going into the System tab. When you're trying to install a new game, it'll be easier to free up space on your hard drive, too. The system will now suggest which games can be deleted to make enough room for the new install, and the installation process now begins automatically once you have enough space.
Lastly, the OneGuide button on the Xbox Media Remote can now be programmed to open any media app instead of OneGuide.
Looking further ahead, Microsoft is currently testing the 1905 update with Preview Alpha ring Insiders, and even 1910 builds have been released if you're in Preview Alpha Skip Ahead. It's currently unclear what new feature those updates will bring, though.