[Closed] Stores.dll fails WACK Supported API Test due to reference to System.Text.Encoding.ASCII

When I try to integrate Unity IAP into my Windows Store project (including Windows Phone 8.1, Windows 8.1 and UWP), I found that Stores.dll in Unity IAP fails WACK Supported API Test. More specifically, in the implementation of MoolahStoreImpl.GetStringMD5, it uses System.Text.Encoding.ASCII, which is not supported in Windows Store.

This issue is blocking our integration of Unity IAP. Is there a way to work around it or will it be possible to get an official fix soon?

There is a discussion here on this issue, we are looking to address it in the near future [Solved] Does Unity IAP still support Windows 8.1?