See this MSDN article.

.NET 4.5 libraries contain the class System.IO.Compression.ZipArchive.
At this moment it’s in preview stage and it’s difficult to predict whether the existing .NET libraries (like Ionic.Zip) will be deprecated by this new feature. Unfortunately the Microsoft way at this moment is to deliver something that works, but only in a limited set of scenarios. For special scenarios additional code must be written.