https://learn.microsoft.com/en-us/officeupdates/current-channel 未更新
4/23 追記
https://learn.microsoft.com/en-us/officeupdates/current-channel#version-2604-april-21
追記終わり
https://learn.microsoft.com/en-us/officeupdates/current-channel-preview#version-2604-april-21
