EF 4.1 Update 1 (EF 4.1.1) has been released a few days ago.

http://blogs.msdn.com/b/adonet/archive/2011/07/25/ef-4-1-update-1-released.aspx

The important point is also EF 4.1.1 Code First Migrations August
2011 CTP
Released:

http://blogs.msdn.com/b/adonet/archive/2011/07/27/code-first-migrations-august-2011-ctp-released.aspx

This is really important for people working with Code-First because it allows
to change your Entity Model and then upgrade your database instead of having to
re-create the database from scratch.

Even though EF Code-First Migrations is still a CTP, it is something just for your development time, it won't impact to your production code dependencies which are RTM dlls/assemblies (EF 4.1.1).

EF 4.1.1 (Update) is a release version (RTM).

Cesar.