Qt5 -> KDE5?

Markus Slopianka markus.s at kdemail.net
Mon May 9 23:35:17 BST 2011

Am Montag 09 Mai 2011, 18:03:18 schrieb Olivier Goffart:
> Hi,
> With Qt5 around the corner[1], I think it is time to start thinking about
> KDE5

Sad to see that even our own guys still don't get the rebranding even after almost two 
Qt 5 results in no need to think about "KDE5" because there will be no such thing as 
The only thing Qt 5 does is to enforce "KDE Platform 5" because of the broken binary 
KDE Plasma Workspaces can stay at 4.x and build on Platform 5 unless KPW magically becomes 
something totally different that justifies a major version jump. Change of the back-end 
alone does IMO not justify a big version jump for KPW just as Phonon did not jump to 5.0 
just because xine was deprecated in favor of VLC and GStreamer. Nothing from KPW 
guaranties binary compatibility which IMO means that the user workflow has to change 
dramatically for a big version jump.

If classic QWidgets stay, I also don't see why KDE Applications need to jump from 4.x to 
5.0. Most will just be recompiled to use the new Platform 5 without any huge GUI 


> Raw summary:
>  - Qt5 is planed to be released in about one year from now if everything
> goes well.
>  - It should be mostly source compatible with Qt4, and is just an
> opportunity to break binary compatibility.
>  - QWidget just stay for compatibility. All focus is put on QML. Do not
> expect new development on QWidgets from Nokia.
>  - The "OpenGouvernance" should finaly come into light, meaning we (as
> KDE), can contribute easier to Qt.
> I guess it make sens, as Qt breaks binary compatibility, to do the same in
> kdelibs.
> Does that mean "KDE 5"? or "KDE SC 5"? Not necessarily.
> We can break binary compatibility, and change the .so version of our
> library without changing the major version of KDE itself.
> But I think it would anyway still be a smart move to do it.
> And I think this is a perfect opportunity to get some KDE class in Qt as we
> planed. [2]
> Some item we might want to think about:
>  - Do we want "KDE 5" to be a big change, or just a small increment?
>  - Do we want to focus on QML, or stay with QWidget?
>  - Shall we try drive Qt5 based on KDE5's need?
>  - Do we have more visions for what KDE5 should or should not be?
> I guess there is as many opinions as people involved :-)
> Many things to think about, and that can be discussed further, and decided
> in Platform11 [3] (I will be there)
> But in my opinion, if there is something we should learn from the KDE4
> transition, it is not to be too ambitious.

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