Today is a major product launch for Microsoft for new app STORE, WIN11, and Office 2021.  WIN11 support is immediate & WIN10 will be added in a few months.

Microsoft Launching New App Store Alongside Windows 11 — Redmondmag.com

Microsoft announced this week that its new Microsoft Store site will launch on Oct. 5, alongside new Windows 11 and Office 2021 product releases.  The new Microsoft Store will have support for Windows 10 users, in addition to Windows 11.  This is a revamped “open Store for an open platform,” meaning that it supports apps built on various application development platforms.  The new Microsoft Store will even house the app stores of other software developers & will be getting Amazon and Epic Games store content.