[Development] Qt’s UWP backend will be dropped in Qt 6

[Oliver Wolff]

Hi,

with Qt 6 approaching it is time to have a look at our set of supported 
platforms.

One candidate for removal of support was our port for Microsoft's 
Universal Windows Platform (UWP). Some considerations about dropping 
this support have been communicated on Qt's development mailing list in 
April last year [1] and there were some discussions about this topic on 
the corresponding bug report [2]

During this year's Microsoft Build conference Microsoft announced the 
unification of Win32 and UWP for their IoT offering. In general, it 
looks like Microsoft is stepping away from their strict stance about the 
usage of UWP technology and the Windows Store. Getting a classic Windows 
application into the Windows Store is much easier nowadays and will be 
even simpler in the future. Microsoft's new direction in their IoT 
offering will bring more "classic Windows development" into the IoT 
world and there will be no need for a dedicated UWP port.

With this official Microsoft standing in mind our current plan is to 
drop our dedicated UWP platform backend for Qt 6. According to these 
plans the last Qt version that will support "native Qt UWP application" 
will be Qt 5.15.

There are two main reasons for this decision:
- The number of bug reports for the port as well as the company's user 
data indicate that there is not much interest in the port.
- Keeping the port alive and up to date is a big effort (I will spare 
the details but can of course elaborate further if there is interest). 
The company decided developers' time is better spent in other areas. By 
dropping the dedicated UWP port the company's Windows developers can 
concentrate on our "classic" win32 port and other areas that didn't get 
the attention they needed.

All in all, we hope that dropping support for the UWP port will result 
in higher quality for other parts of Qt. From the company's point of 
view this benefit outweighs the "reduced cross-platformness of Qt" as 
the port is not used that much anyway.

Backends that use UWP APIs (bluetooth, sensors and positioning for 
example) are not affected by this decision and there will most likely be 
additional backends that use new MS technology.

Best regards,
Olli

[1] 
https://lists.qt-project.org/pipermail/development/2019-April/035673.html
[2] https://bugreports.qt.io/browse/QTBUG-74755