Comment # 1 on bug 1088576 from Wolfgang Bauer

(In reply to Axel Schwank from comment #0)
> Could this fix be integrated in Leap 42.3, please?

No. It causes ABI incompatibility.
See (the first part of) bug 1054374, in particular comment#10:
> Submitting this as a maintenance update is bad for several reasons:
> 
> - It's a new feature. Normally this needs to get extensive testing, this
> feature isn't available in any released Qt!
> - This breaks private API and ABI. Which means several applications need to be > rebuilt, which is not feasible with maintenance updates.
> Otherwise those applications either fail spectacularly with missing symbols
> when you try to open the printer dialog, just crash or.
> It's just a select few, but even if there is a single one out of our reach
> (packman, other OBS projects), it'll break.

It will be in 15.0 though.

And you can find Qt 5.6.2 packages with the patches backported here (as
mentioned in the other bug report), if you want to risk it:
https://download.opensuse.org/repositories/home:/jirislaby:/kotatko/openSUSE_Leap_42.3/

*** This bug has been marked as a duplicate of bug 1054374 ***