The secret to Win32 apps on Polaris may be RAIL and VAIL

We have heard that Polaris, a future version of Windows 10 that is designed to shed much of the legacy of the venerable operating system, including direct support for Win32 apps, may still offer these apps via a remote desktop-style solution.

Now Italian blog claims to have some more information on how Microsoft intends to offer this feature without a massive performance penalty.

The solution is apparently in the acronyms RAIL and VAIL.

RAIL stands for Remote Application Interface Layer, and would presumably offer Win 32 applications access to the legacy Win32 APIs which Microsoft decided to remove, running safely on a remote Azure server.

VAIL is for when a network connection is not available and stands for  Virtualized Application Interface Layer. This would presumably offer the same service but running in a local container and allow Centennial apps to still function despite the core OS not offering the Win32 APIs needed anymore.

According to’s sources Polaris is likely to launch initially without support for these remote API calls in 2018 (probably on specialized devices where they wont be missed) but will add them Polaris v2, which is aimed at regular laptops and desktops.

In fact, (unsurprisingly) expects the Surface Phone to launch at the end of 2018 with support for both the Andromeda shell and also version 1 of the Polaris shell, and to be able to switch between the two.  This means the rumoured Surface Phone will not initially be able to run Win32 applications, but that they may be added in a later update.

We are unfortunately unable to verify this news, but what we can say is that for such an ambitious project Microsoft will need to execute like clockwork, something we have not had a good experience with in recent years.

What do our readers think? Let us know below.

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