[Qt-interest] How qt version sensitive are qt applications?

[Robert Hairgrove]

Andreas Pakulat wrote:
> On 27.03.10 16:09:16, Kārlis Repsons wrote:
>> Considering the problem, lets say, Qt application was built for Qt version N1, 
>> but on the host system there is Qt version N2 -- in general, for what N1 and 
>> N2 will that application run on host? Is it really that N1==N2 for running?
> 
> Qt/Nokia guarantees that an app compiled with Qt4.x executes with
> Qt4.x+1, that is it will start up and will generally work, but you may
> find behavioural differences sometimes. In what way those affect your
> app depends on which classes you've used.
> 
> The other direction is only possible within patchlevel releases, so
> compiling your app with Qt4.x.y and running it on Qt4.x.y-1 is possible,
> but not running it on Qt4.x-1.
> 
> Andreas
> 

This would mean that if I want my app to work with ANY Qt4 version, I 
must compile it with 4.0.0. I thought that all major releases were 
backwards compatible? I.e., if someone had Qt 4.5.x installed, and I 
compiled my app with Qt 4.6.x, it should still work OK under the lesser 
4.5.x but not under Qt 3.x.