# How to change version of c# framework? default is .net 4?
**URL:** https://community.haxe.org/t/how-to-change-version-of-c-framework-default-is-net-4/811
**Category:** Haxe
**Created:** [June 26, 2018, 8:00am UTC](https://community.haxe.org/t/how-to-change-version-of-c-framework-default-is-net-4/811 "2018-06-26T08:00:51Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Zhan](https://community.haxe.org/u/Zhan)
#### Post date: [June 26, 2018, 8:00am UTC](https://community.haxe.org/t/how-to-change-version-of-c-framework-default-is-net-4/811/1 "2018-06-26T08:00:51Z")
how to change version of c# framework? default is .net 4?
I want to compile code lib .dll use for unity
how to change dll frame version to .net2?or 3?
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### Author:  [@kLabz](https://community.haxe.org/u/kLabz)
#### Post date: [June 26, 2018, 8:11am UTC](https://community.haxe.org/t/how-to-change-version-of-c-framework-default-is-net-4/811/2 "2018-06-26T08:11:06Z")
You can find information on the haxe manual: [target cs](https://haxe.org/manual/target-cs-external-libraries.html)
You can add versions not handled by [hxcs](https://github.com/HaxeFoundation/hxcs) (they have 2.0, 4.0 and 4.5) by creating directories according to the haxe manual and place `System.dll` and `mscorlib.dll` in there (also maybe `System.Core.dll`, depending on the version I suppose)
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### Author:  [@Zhan](https://community.haxe.org/u/Zhan)
#### Post date: [June 26, 2018, 9:39am UTC](https://community.haxe.org/t/how-to-change-version-of-c-framework-default-is-net-4/811/3 "2018-06-26T09:39:25Z")
> [@kLabz](#):
>
> by creating directories according
thank you ,it’s work!