For example in the following label I want to use SmallCaps, but they only show up on Windows 8 and higher. On Windows 7, there are just normal letters.
<Label x:Name="servername" Typography.Capitals="SmallCaps" Content="Server xy" VerticalAlignment="Bottom" FontSize="15" Margin="10,0,10,31" Padding="5,0" FontWeight="Light" Height="19" HorizontalAlignment="Left" SizeChanged="servername_SizeChanged"/>
I'm using .NET Framework 4.5 and the font is Segoe UI Medium (and in some other labels Segoe UI Light), which is installed on both systems.
As you may know,
Typography.Capitals
support is provided by the OpenType font family itself: https://msdn.microsoft.com/en-us/library/system.windows.documents.typography.capitals(v=vs.110).aspxSmall caps support for Segoe UI was added for Windows 8. The Windows 7 version of Segoe UI does not support small caps.
https://littlenewthings.wordpress.com/2013/08/07/segoe-ui-gets-a-facelift-in-windows-8/
I'm unsure of the possibility and legality of packaging up the updated version of Segoe UI for use in your own WPF application.