API Changes from 3.7 to 5.0

I am looking for something that references the API changes.  I've tried searching all over this site and the documentation and just can't find it.

As one example, we are using the class Telerik.Cms.Web.InternalPage in some of our custom code and calling the GetTheme method that passes in the IPageContent class as a parameter.  So, is there something that describes the changes in detail so I can search for say InternalPage and see what new object takes it's place if one does?

Thanks