Convert a C# Library to Net.Core

As .NET Core is getting nearer, I will start to convert our Library to NET-Core, so that it could be used from our old Code (Net 4.5) and Net Core! But for me it is not clear what Type should my Library be. I've no "Net-Core" Project Type in VS2015! Do I need to use old school "PCL" Library? Or how do I do it?

But for me it is not clear what Type should my Library be. I've no "Net-Core" Project Type in VS2015! Do I need to use old school "PCL" Library? Or how do I do it?

Use the Web > Class Library (Package) type.

• File > New > Project
• Web > Class Library (Package)

The screenshot is from Visual Studio Community 2015 Update 2 with ASP.NET 5 RC1 installed. Its project.json targets two frameworks: .NET 4.5.1 and .NET 5.4 (renamed to .NET Core.)

{
  // other properties deleted for clarity

  "frameworks": {
    "net451": { },
    "dotnet5.4": {
      "dependencies": {
        "Microsoft.CSharp": "4.0.1-beta-23516",
        "System.Collections": "4.0.11-beta-23516",
        "System.Linq": "4.0.1-beta-23516",
        "System.Runtime": "4.0.21-beta-23516",
        "System.Threading": "4.0.11-beta-23516"
      }
    }
  }
}

Tip. When you're upgrading your class library, run the .NET Portability Analyser on the existing code. It will show the classes & members that must change.