As I transition to 4.2, I notice that some free contents from 4.1 needed to be downloaded again. I reckon the Example Content has an added content. But what about the others, like Elemental, Memory, and Tappy Chicken?
Does this mean that I have to download them again?
When Epic Games releases a new version of the engine, they may elect to add to or change a piece of marketplace content. When they do, it comes as a separate version. This allows Epic to release updates to, say, Tappy Chicken that take advantage of new features introduced in a new version of the engine while at the same time still making Tappy Chicken available to developers who are still using an older version of the engine.