KPageDialog - What happened to source compatibility?

[Albert Astals Cid]

I think to remember one of the goals was that the KF5 would be as source 
compatible as possible.

Now i see that KPageDialog is not a KDialog anymore and thus setButtons, 
setDefaultButton, setButtonGuiItem, etc are not available in it anymore.

Now, i *do* understand that for the tierization some rework was needed, 
otherwise you would not be able to get KPageDialog to be of tier1, but I think 
that either of this should have happened:

 a) K4PageDialog exists in kde4support for all of us that are happy not being 
strict about library dependenices
 b) KDE5PORTING.html has notes on how to port "KDE4 KPageDialog" to "KF5 
KPageDialog" if it is really trivial.

Sadly I could not find either of them :-/

Cheers,
  Albert