When Microsoft unveiled Windows 11 back in June, it made a big deal about Android apps coming to Windows through the Amazon App Store. However, this capability was not present in the launch version of Windows 11. Although we have seen the Windows Subsystem for Android brand pop up from time to time, there is little known about its implementation or when it will become available. However, Microsoft has now published guidance for developers about how they can optimize their Android apps for Windows.
The detailed documentation can be seen here and was first spotted by WalkingCat (@_h0x0d_ on Twitter). In it, Microsoft has noted that Windows Subsystem for Android (WSA) will be silently installed in the background as soon as you install the Amazon App Store or an Android app from the Microsoft Store for the first time.
A dedicated settings app can be used to toggle hardware-accelerated graphics, the behavior of the subsystem to be ephemeral or persistent, and developer mode, among other things. Microsoft has also provided guidance to developers about how they can update their app's code to respond to keyboard and mouse inputs. Additionally, the company has outlined debugging and window resizing details too. The purported settings app can be seen below, courtesy of WalkingCat:
WSA utilizes a virtual machine (VM) configuration which provides interoperability with the Android Open Source Project (AOSP) framework and other input devices. In terms of security, Microsoft has mentioned that:
Windows Subsystem for Android performs per-file encryption that is software-based, and thus provides limited protection. App developers should not expect their saved state to be secure.
Both Windows kernel-mode drivers and Windows applications running at medium integrity level (IL) can inspect arbitrary Android containers and Android app memory. There are no plans to add detection for cheats/macro/bot/suspicious behaviors detection in the short-term.
Interestingly, the documentation also says that the Amazon App Store will offer only a limited set of apps curated by Microsoft and Amazon initially, but it's likely that the list will expand with time. Although WSA supports ARM via emulation, this will have a performance impact so Microsoft has recommended developing apps optimized for the x86-64 architecture. While the documentation still doesn't hint at a firm release date for a preview or general availability, it appears that we are nearing that unknown date.