Changing Versioning Settings

Question

Why am I not able to change the "Draft Item Security" in versioning settings of Wiki page?

And

Isn't there any option to change the versioning settings of a Web Part Page?

Answer 1

To be able to activate the second option button of Draft item security you need to apply minor versioning (tick the box of minor versions), to be able to activate the third option button of draft item security you need to activate page approval (Require content approval for submitted items? yes)

I do not understand what you mean by versioning settings of web part page.

The settings do not belong to the page, but to the page library that contains them (Site Pages or Pages)