This update should not require you to have to reboot unless you happen to have Notepad.exe open. This update only revs the version of the OS and includes an updated binary version of Notepad.exe and nothing else. It does introduce the following issues to be aware of.
Make sure you’ve setup Mixed Reality before taking this update.
After installing a language pack or feature-on-demand like .NET 3.5, your PC may be offered this update again and fail.
This update will only remain available until the next WIP Fast build is released.
You can head over to windows updates to get this release.