Unity version 4.2 is available now and there are some important stuff that you can read here about this new version: http://blogs.unity3d.com/2013/07/22/unity-4-2-has-arrived/
More free tech
We’ve decided to make a number of existing Unity Pro features available to users of the free version of Unity:
Realtime shadows (one-directional light only; hard shadows only).
Text-based serialization of materials, prefabs, scenes etc. for easier version control.
NavMesh baking (OffMeshLinks still require Pro).
Now, games created using the free version of Unity can benefit from realtime shadows and game actors navigating intelligently. In addition, as a developer using the free version of Unity you can cooperate with your colleagues using any version control system, because text-based serialization no longer requires a Unity Pro license