https://github.com/aspnet/EntityFramework/wiki/Roadmap
The schedule for the initial release of EF Core is in-sync with the ASP.NET Core
https://blogs.msdn.microsoft.com/webdev/2016/02/01/an-update-on-asp-net-core-and-net-core/
rename ASP.NET 5 to ASP.NET Core 1.0
https://msdn.microsoft.com/en-us/data/jj574253.aspx
EF (or EF 3.5) = The initial release of Entity Framework was included in .NET 3.5 SP1 and Visual Studio 2008 SP1
EF4 = Visual Studio 2010, .Net Framework 4
EF5 = This release can be used in Visual Studio 2010, target .NET 4.0 and .NET 4.5
EF6 - is included in Visual Studio 2013, Visual Studio 2012 and Visual Studio 2010 (runtime only) to write applications that target .NET 4.0 and .NET 4.5.