http://lists.qt-project.org/pipermai...ne/021979.html

The jump to QT5.2 was supposed to have been traumatic for the Sailfish team, with no sign of planning for a new rebasing of QT appearing since.

Presumably, they'll have to move eventually, so would an LTS release in Dec15 be the time to [start] that process?

Can someone explain what's the Problem with updating a minor release of Qt on Jolla? Do the Sailfish OS Silica components only work with a specific Qt 5.x version? Isn't Qt 5.x supposed to be backward compatible with previous 5.x versions?

So I wonder why Ubuntu Phone already uses Qt 5.4 and Jolla found it difficult to update from 5.1 to 5.2 last year. Or was there any new Qt update within the last 2-3 OS updates in the meantime I missed?

I thought I read that the problem with the move to 5.2 wasn't so much about incompatibility with the version they were on before, but with the immaturity of the target version at the time, meaning they had to do a lot of working around bugs and performance/memory issues. You'd think an LTS would be an easier target in that regard.

And Ubuntu doesn't care so much about performance and memory issues, as long as they can run the latest and greatest version.

The move from 5.1 to 5.2 was a big move. Large changes in the renderer, a totally new JavaScript engine, and a lot of other usual changes.

It took a team of people (let's say, ~2-4 people) some months (let's say six) of work before it was ready for the rest of the company to take a look at it, and unfortunately some rough seas elsewhere in the company meant that it took even longer after that to mature properly (another 3-4 months).

In my opinion, the move to subsequent versions is less drastic, although there is still a (constant) influx of bugs and performance regressions to fight against -- and this together with the tablet development means that there likely isn't going to be a lot of priority to this type of work unless it brings substantial benefits in another area, much as I'd like to see it happen.

When it does happen, I imagine that it is likely to happen a lot more piece-by-piece: QtMultimedia is already being upgraded in a future release because it's needed for some other bits and pieces, for instance.

And to answer the initial question: an LTS release is a very good thing from Sailfish's perspective. It means there's a reasonably solid base that can be focused on (and collaborated on with other people), rather than a constant train of moving targets where Sailfish would either be on the bleeding edge or constantly far behind.

And the fact that they're basing Ubuntu Phone versions on the desktop version (aligning). So if the desktop version has Qt 5.4, then the Phone version will have 5.4 as well. Jolla only has the phone (and the tablet WIP).

Thanks, w00t.

Would you imagine that Sailfish might make use of the some the newly stabilised features in Qt?
QT3D is one example, i'm sure there are others too.

Never say never, but I don't see e.g. the immediate switch to a 3D interface coming one release after the initial introduction of the 3D library, for instance

Qt 5.5 just got released:

http://blog.qt.io/blog/2015/07/01/qt-5-5-released/

I still don't understand why I can use the latest Qt version with (Desktop) Linux, Windows (Phone), Mac, Android and even on Raspberry Pi but not on Jolla?

Hope that SFOS 2.0 has some more recent update.

I assume because the Jolla it limited by its hardware and it has to be ensured that Qt 5.5 won't bring any determinal performance issues, since on PCs its not as much of an issue, and Android Qt isnt the primary toolkit, while for Jolla the UX is built on Qt, also what APIs does it bring that you want?