What are the requirements for developing applications for Windows XP and higher?

Question

.NET

I use MS Visual studio 2015, C#, Telerik, .Net framework.
All applications written using these "technologies" work fine on windows 7.
But the task was to write software for Windows XP and higher.
Those. Windows XP, 7, 8, 10.
What are the requirements for developing applications for Windows XP and higher?
Specifically, I'm interested in the .Net framework.
Under Windows 7 it is 4.5, on Windows XP it will not get up (without strong shamanism). What version of the framework would you recommend to use under Windows XP and higher? And is there a significant difference?
How do you feel about Telerik? Is there another standard UI on which most large companies develop and which can be considered a de facto standard?

Answer 1

What are the requirements for developing applications for Windows XP and higher?

use a maximum of .Net framework 4.0 (not higher, you can lower). And the syntax of c# 4-5 versions, because XP has no idea what this means on c#7 version:

string my_text = "Hello";
string nickname = "ogpol32!";
Console.WriteLine(string.Format($"({my_text}, {nickname})"));

you can also add that try to make the application as undemanding to computer resources / memory as possible (although this applies to any application for any OS)
and (ideally) try to use as few crutches and additional (non-native) libraries in the project as possible. In general, the simpler the better.
essential. I personally write under / on .Net 4.5 and (of course) fly with XP ... Between 4 and 4.5 the difference is quite significant: especially regarding exception handling and multithreading. But alas and ah... on .Net 4, you will have to sacrifice "syntactic sugar" as a result of which, the code will be less readable and convenient.
unfortunately I didn’t use it (and I can’t tell you, except that Telerik is imprisoned for .Net 4 Client (not lower)
in general, use .Net framework 4 Client and version c # 4-5 and may the force be with you ...
upd

Answer 2

The latest supported version of Net for XP is 4.0, it is actually logical to use it