KF 5 & C++14?

[Friedrich W. H. Kossebau]

Hi,

I just saw that at least kimageformats, knewstuff & kquickcharts all set this:
    set(CMAKE_CXX_STANDARD 14)
    set(CMAKE_CXX_STANDARD_REQUIRED ON)

Which ignores a bit that so far C++11 has been the minimum standard officially 
supported in/by KDE Frameworks (by mainly following what Qt 5 supports).

Compare also the current text of the policy
"Frameworks compiler requirements and C++11":
--- 8< ---
The following minimal compiler versions are supported by KDE Frameworks:
* GCC 4.8
* Clang 3.3
* VS2013 (MSVC12)

This means all of the C++11 standards can be used. 
--- 8< ---
* https://community.kde.org/Frameworks/
Policies#Frameworks_compiler_requirements_and_C.2B.2B11

What to make of this? Might it be the time to raise the bars a bit, and how 
much? Surely the lower limit is what the oldest Qt version currently supported 
by KDE Frameworks claims to support: https://doc.qt.io/qt-5.12/supported-platforms.html

Should we go above this?
Or should kimageformats, knewstuff & kquickcharts be fixed to use C++11 only 
again?

No own opinion, so far only stumbled over what seems a policy breakage.

Cheers
Friedrich