It will probably be a while before moving beyond .NET 4.0. The current code of AdvancedHMI does not use any features beyond 4 and there are a number of users still using VS2010 and XP that will not work beyond .NET 4.0
Now that version 3 of AdvancedHMI has reached a feature rich and stable version, the next major version is in the planning stages. The next major version will probably move to all of the latest Microsoft technologies including Windows 10, XAML, Universal Apps or WPF.