Blockquote
Is it more important to have a compositing version that uses the last version of Qt, or to have something that is production-ready?
lol, I’ve so much seen this argument during my work in industrial domain…
Easy, none of them: False dilemma - Wikipedia
First production-ready is not a “simple definition” that anyone are agree with its bound. This is a per-project and per-people definition. We need to stop to use it as excuse to anything.
About Qt4: do you think that using Qt4 is production aware if I need to say to any team that the software they use is deprecated by those who made it and no bug-fixes will be released anymore?
They will get a smile 
Sure they don’t care about Qt4 vs Qt5, they want a software that can be used everyday and works without knowing how to install it.
BUT…
To make this last sentence a reality, we (developers) need to have right tools.
This is our requirement. We don’t sell Qt (we even not sell anything in fact).
But we need something strong at development level, to make things strong at user level.
It’s a well known causal effects.
For the fun, this is a real story.
I’ve work for a customer last year (world big one in TV broadcasting domain) that has exactly followed the gimmick “no fancy dev tool, no upgrade, don’t touch working code, only customer requests matter”.
Today all the code is java 5, tons of deprecated libraries with known bugs, running on a custom and manually maintained gentoo.
After 10 years of existence they decided to change for an Ubuntu has the tech lead of the
project and developers were upset to maintain libraries in Gentoo.
But it was too late, most of senior dev and architect have leaved the project as they were upset to never follow the usual technology improvement (not the only one reason for sure, but all ones have given this one).
Consequences: only 1 senior SW remains on the project, nobody understand the code (+1M lines).
But customers are happy with the SW in fact! … except that now they will not get much support for it as the team is reduced to the strict minimum to live and improvements are made at high cost.
Only because managers don’t care about developers.
«Happy Developers Make Better Software»
«No Devs, No Software»
Sorry @devernay if you think I’m a bit harsh with you, nothing personal, but you need to understand that Natron is an opensource software that needs developers first or the project will die. No ones is going to help you in the FOSS world if the technology behind doesn’t appeal them.
You and Alexandre have made a fantastic job: give it now a good and long life.
PS: yes, I’ve run the tests… all goods excepts 3 ones due to non-built pluggins. As this first stage was only a proof of concept, I’m happy with that