Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

I think I already covered this a few posts above you. It's not a trivial effort like you seem to assume it is, and the effort going onto that is effort that isn't spent elsewhere (other useful bugfixes/features, tablet work, etc)

It doesn't. You can watch the activity yourself on http://github.com/mer-qt/.

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

When you say you can "use" the latest Qt with all these operating systems, I believe what you mean is that you can run programs written using Qt on those systems. Other than desktop Linux, none of those OSs actually use Qt internally for anything (and only some distributions of Linux use Qt).

I would guess that, if you really wanted to, you could build an executable on Qt 5.5 and run it on a Jolla; you simply wouldn't be able to take advantage of Sailfish's GUI. You'd need to include your own UI graphics libraries into your app, much the way Qt works on Android. (Gah, I really, really hate the way Qt works on Android; I've been pulling my hair out trying to create a UI for my apps that looks at all reasonable. Creating a reasonable UI using Sailfish is so much easier...)

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

You can! All you need is somebody who'll package a new version of Qt for SFOS, which should be installed "beside" SFOS main Qt version. (Windows phone & Android doesn't provide Qt themselves, so there is no reason that we expect Jolla to provide this).

Being able to install latest Qt version on Jolla is completely different from the Qt version used by SFOS.

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

True, but isn't actually the point of newer Qt point releases also to bring performance improvements and lot's of bug fixes?
Don't you see the irony that a device what is build on the premise of Qt lags the newest improvements of the toolkit compared to all other platforms?

I think it would be really great to have an updated Qt WebKit or even the new Qt WebEngine module. All apps rendering web content including 3rd party web browsers would greatly benefit from it. Also Jolla could switch finally to GStreamer 1.x with Qt Multimedia. Besides this the SFOS SDK could use a newer version of Qt Creator for development.

Qt 5.2 still used in the latest SFOS came out the same time as the Jolla phone in December 2013. Don't you think it's time for an update at least for SFOS 2?

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

I never assumed that's a trivial effort.

But keeping a fork of a specific version longer gets more expensive over time. If the 5.1->.2 update was already that painful I wonder how difficult a higher update will be?

Ok, I see it's still based on the Qt 5.2.x migration work last year.

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

Actually, that's a pretty good question. Many organizations do maintain the policy of limiting "minor" releases to just performance and fixing bugs, but this doesn't apply to everybody. Certainly, Qt has added and removed features whenever they wanted; heck, QML itself was introduced in Qt 4.7.

In short, the numeric value of a Qt release isn't a good indicator of just how much Qt has changed in that release.

The fundamental premise of Qt is ease of cross-platform app creation. I don't see how that should make updating an operating system any easier...

Moreover, Jolla is selling itself on having a superior mobile device user experience on top of a (mostly) open operating system. This really has nothing to do with what version of Qt they use; their selling point could still stand, even if they moved away from Qt altogether.

The way Qt has messed around with their web client software is far, far more than just a simple performance enhancement, and requires at least a little amount of effort to properly adjust to. Similarly, GStreamer 1.x has some interesting differences over 0.10. And I don't see any significant value in having the latest version of Qt Creator; I'm currently using Qt Creator 2.4.1 (SDK 4.7) for Maemo work, Qt Creator 3.1.2 (SDK 5.2) for Sailfish work, and Qt Creator 3.3.0 (SDK 5.4) for Android work. They're all pretty much identical in terms of how they work, other than that they all support some radically different Qt features.

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

The general process the Jolla guys work with is to get their changes upstreamed to the latest Qt and then back-port them to Qt5.2 for use on the Jolla. This is initially more work but it means that the two branches are converging not diverging.

GStreamer 1.0 is a prime example of this, its currently in testing for the next release (fingers crossed)

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

Yes, but fragmentation goes against cross-platform.
We are starting to see the same problems with Qt, than with other eco-systems (like Android) : the more different Qt versions there are in the field, the more difficult it gets to make cross-platform things, except if using only the lowest common denominator.

Someone who starts to write an application today, will use Qt5.5 on desktop, but would not be able to directly use canvas3D/qt3D/QtLocation/Bluetooth4LE on Ubuntu touch, and a lot less in Qt5.2 on Jolla.

That is what is bad in this situation. On the other hand, not spending all their time to try to follow closely each release of Qt is legit.

About fragmentation, Silica also doesn't help as it can't run on anything else than Sailfish itself. But it looks great ;)

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

The general behavior has been kept the same, but it is getting a lot more efficient when using refactoring tools in the last versions. Kits and devices has also seen a major overhaul since 2.4.
And QtCreator is not tied to a specific version of the Qt toolchain, it is only an IDE. I always use the last QtCreator version for all my toolchains (Qt4.x and Qt5.x), I even develop with it for embedded devices with no OS and no Qt.
So Jolla can update their SDK without changing the Qt version running on their OS, if they'd see the need.

Re: QT5.6 (Dec15) to be Long Term Support - implications for Sailfish?
 

You're telling me! ;) I've given up on trying to create a single unified UI for my own apps, which is why I've got a different version of the Qt SDK up and running for each of the devices I'm targeting.

However, I have to admit that the non-GUI parts of Qt really do work as advertised. I was able to get the back-end of my Pierogi app up and running on Android in just a couple of days, and was using it to control TVs and other devices. I just recently threw Linguine at Qt on Android, and was quickly pulling down podcasts with it as well. It's just that I can't possibly use the same Qt GUI for both Maemo and Android. :(