title: Simplest way to target multiple framework in nuget?
body: <p>I created a library that uses: generics, extension methods and <code>Func</code> delegate. 
  <code>Func</code> delegate is most new feature to .NET (version 3.5) in the library. When I published it to nuget, the project was targeting the .NET version 4.5.2 but when I tried to install it to a project that target version 4.5, it failed.</p>
  
  <p>How to ensure that the package will be installed on any project that targets .NET 3.5 and later versions, should I change the target framework in the library to 3.5 or I should use the directory convention, and create separate dll for every framework, explained here:</p>
  
  <p><a href="https://docs.microsoft.com/en-us/nuget/create-packages/supporting-multiple-target-frameworks" rel="nofollow noreferrer">Supporting multiple .NET framework versions</a></p>