can't add in to .net framework 4.0 project

[SealinRepo]

Hi:
I have a project using .net 4.0, and extended the "async await" keyword, but install this dependency failed, can I use it in my project?
best wish.

[bezzad]

Hi, @SealinRepo

This repository is written in .NetStandard2.0 and according to the the following link, can't support the .Net40. And the minimum version of .NetFramework that can be supported by this project is .Net4.6.1.

I try to downgrade the .net version but .Net40 has not many dependencies on this project.
But multiple target framework support projects with .Net45 and later versions.

Thanks