For people who read the announcements already know that CodePlex will be turned off on December 15 of this Year. For people who have not yet noticed CodePlex 2017-12-15.
Now what are we going to do? Is there a solution?
Yes, let's all switch to GitHub.
What ? Seriously ?
Yes you can check on the blog of Brian Harry's in https://blogs.msdn.microsoft.com/bharry/2017/03/31/shutting-down-codeplex/.
"We migrated too. As many of you know, Microsoft has invested in Visual Studio Team Services as our “One Engineering System” for proprietary projects, and we’ve exposed many of our key open source projects on GitHub (Visual Studio Code, TypeScript, .NET, the Cognitive Toolkit, and more). In fact, our GitHub organization now has more than 16,000 open source contributors – more than any other organization – and we’re proud to partner closely with GitHub to promote open source."
Microsoft has created a guide how to migrate from Codeplex to GitHub available at https://codeplex.codeplex.com/wikipage?title=Migrating%20to%20GitHub.