if TOSVersion.Major = 10 then // 高版本的Delphi（比如Berlin）可以这样写
ShowMessage('Windows 10');
或者：
if Win32MajorVersion = 10 then
WIN10以后如果Manifest中不写支持WIN10的话，获取版本号的API获取的是6，最新版的Delphi的manifest中写了支持WIN10，所以没问题。
老版本Delphi要自己写manifest中间加上
<compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
<application>
<!-- Windows 10 -->
<supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
<!-- Windows 8.1 -->
<supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>
<!-- Windows Vista -->
<supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}"/>
<!-- Windows 7 -->
<supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>
<!-- Windows 8 -->
<supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
<!--This Id value indicates the application supports Windows Vista/Server 2008 functionality -->
<supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}" />
<!--This Id value indicates the application supports Windows 7/Server 2008 R2 functionality-->
<supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
<!--This Id value indicates the application supports Windows 8/Server 2012 functionality-->
<supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
<!-- This Id value indicates the application supports Windows Blue/Server 2012 R2 functionality-->
<supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
<!-- This Id value indicates the application supports Windows Threshold functionality-->
<supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
</application>
</compatibility>
http://bbs.2ccc.com/topic.asp?topicid=529101