Change of Modifer in CSLA4.5

Hi,

I was trying to upgrade my application from CSLA 4.3.13 to CSLA 4.5, and the code didn't Compiled.

Noticed that

public virtual T Save() of abstract class BusinessBase<T>

is changed to

public T Save() of abstract class BusinessBase<T>

Is there any specific reason of removing the Virtual from the method signature.