The latest build of Windows 10 for the Fast Ring has been released, this time bringing the build number to 18894. Part of the 20H1 update, it has a few improvements and a bit of known issues to check out before updating.

Known Issues

Due to an OS bug, the Your Phone app will not work on this build (20H1 Build 18894). This issue does not impact the Your Phone app if you are in the Slow and Release Preview rings. We expect to have this issue resolved in the next flight to the Fast ring. Appreciate your patience.
There has been an issue with older versions of anti-cheat software used with games where after updating to the latest 19H1 Insider Preview builds may cause PCs to experience crashes. We are working with partners on getting their software updated with a fix, and most games have released patches to prevent PCs from experiencing this issue. To minimize the chance of running into this issue, please make sure you are running the latest version of your games before attempting to update the operating system. We are also working with anti-cheat and game developers to resolve similar issues that may arise with the 20H1 Insider Preview builds and will work to minimize the likelihood of these issues in the future.
Some Realtek SD card readers are not functioning properly. We are investigating the issue.
If you use remote desktop to connect to an enhanced session VM, taskbar search results will not be visible (just a dark area) until you restart searchui.exe.
We’re investigating reports that on certain devices if fast startup is enabled, night light doesn’t turn on until after a restart. (Note: The problem will occur on a “cold” reboot or power off / power on. To work around if night light doesn’t turn on, use Start > Power > Restart.)
There’s a noticeable lag when dragging the emoji and dictation panels.
Tamper Protection may be turned off in Windows Security after updating to this build. You can turn it back on.
Some features on Start Menu and in All apps are not localized in languages such as FR-FR, RU-RU, and ZH-CN.
In the Ease of Access settings, selecting a color filter may not take effect right away unless color filters option is turned off and back on again.
The IME candidate window for East Asian IMEs (Simplified Chinese, Traditional Chinese, and the Japanese IME) may not open sometimes. We are investigating the issue. In the meantime, going to Task Manager and ending the “WindowsInternal.ComposableShell.Experiences.TextInput.InputApp.exe” task from the from the Details tab should unblock you if you experience this issue.
We are aware of an issue with the Bopomofo IME where the character width is suddenly changed to Full width from Half width and are investigating.