Upgrading Existing Project

You can upgrade existing .NET Core projects from using .NET Core 1.0 to .NET Core 1.1 Preview 1. I will show you the new project.json file that the dotnet new command now produces. It’s the best way to see the new version values that you need to copy/paste into your existing project.json files. There are no automated tools to upgrade existing projects to later .NET Core versions.

https://blogs.msdn.microsoft.com/dotnet/2016/10/25/announcing-net-core-1-1-preview-1/

.net core 1.0.1 项目升级到.net core 1.1.0