Update prereq with Beta channel and US only (#2047)

Author: mattwojo

hub/android/wsa/index.md

@@ -6,7 +6,7 @@ ms.author: mattwoj
 ms.reviewer: mousma
 manager: jken
 ms.topic: article
-ms.date: 10/28/2021
+ms.date: 11/01/2021
 ---
 
 # Windows Subsystem for Android™️
@@ -26,7 +26,9 @@ To test your Android app in the Windows desktop environment, a bit of set up wil
 
 ### Prerequisites
 
-Windows Subsystem for Android is currently only available through **preview** in the [Windows Insiders Program](https://insider.windows.com/). Your device also must meet specific Windows 11 requirements. Check the "Windows Subsystem for Android" section under "Feature-specific requirements" on the page: [Find Windows 11 specs, features, and computer requirements](https://www.microsoft.com/windows/windows-11-specifications).
+Windows Subsystem for Android is currently only available through **preview** via the Beta Channel of the [Windows Insiders Program](https://insider.windows.com/) (Windows 11 Build 22000.xxx series) in the U.S. only.
+
+Your device also must meet specific Windows 11 requirements. Check the "Windows Subsystem for Android" section under "Feature-specific requirements" on the page: [Find Windows 11 specs, features, and computer requirements](https://www.microsoft.com/windows/windows-11-specifications).
 
 ### Install the Amazon Appstore