Tuukka Turunen

Introducing Long Term Support for Qt 5.9

Published Thursday May 11th, 2017
29 Comments on Introducing Long Term Support for Qt 5.9
Posted in Biz Circuit & Dev Loop, Qt, Releases

We are pleased to announce that Qt 5.9 will be a Long Term Supported (LTS) release. We have done a lot of improvements to Qt since the previous, Qt 5.6 LTS, and to maximize the benefits for our users we will make Qt 5.9 an LTS release. There will be several Qt 5.9.x patch level releases created during the next three years – also after the next Qt 5.x releases become available. Commercial licensees eligible for technical support will also be able to submit support requests during the whole LTS period.

Since the release of Qt 5.6, our previous LTS release, a huge amount of improvements has been added to Qt. We have done significant work on improving performance, added multiple important new features, and fixed thousands of bugs. Qt 5.9 LTS is a fantastic product that offers substantial improvements over Qt 5.6 LTS. To make it possible for all our users to benefit from these, we will be providing Long Term Support for Qt 5.9.

As with Qt 5.6 LTS, we will be using a phased approach to content in patch level releases for Qt 5.9 LTS. During the first 6 months after release day, an LTS release receives a lot of fixes, including low-priority ones. Then the LTS release enters a ‘strict’ phase where only critical bugs and security issues are addressed. This will ensure the stability of the LTS releases. During the final year of an LTS release the commit policy is ‘very strict’, at which phase we only address severe security issues.

For all new projects, we strongly recommend using Qt 5.9 LTS. The upcoming Qt 5.9 LTS will be supported alongside with the earlier Qt 5.6 LTS release, which still allows the use of the old C++98 compilers. As already noted above, Qt 5.9 LTS offers lots of performance improvements as well as a vast amount of other improvements and bug fixes that are not included into Qt 5.6 LTS. Currently, Qt 5.6 LTS is in the ‘strict’ phase where it only receives selected critical fixes and next it is moving into the ‘very strict’ phase. During this final phase, Qt 5.6 LTS will receive important security fixes only.

According to our LTS promise, we guarantee that Qt 5.9 LTS will be supported for three years via standard support, after which additional extended support can be purchased. During this time, even though following Qt releases (5.10 onwards) are already out, Qt 5.9 LTS will receive patch releases providing bug fixes and security updates. For an LTS release, the amount of patch releases will be higher than non-LTS releases of Qt and we aim to provide these throughout the LTS period. In addition to security fixes, error corrections and improvements provided by the LTS patch releases, we may also add support for new operating system and compiler versions to an LTS release of Qt, when feasible. It should be noted that the deprecated modules and technology preview modules are not subject to the LTS.

Qt 5.9 Beta releases are already available via the online installer, check it out if you have not yet done so. If you do not have the Qt online installer yet, please get it from the Qt Account or the Qt downloads page. We are working hard to further fix and polish it with the target of having the Qt 5.9.0 final out around the end of May 2017.

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Posted in Biz Circuit & Dev Loop, Qt, Releases


jona yang says:

I just wanna say congrats 🙂

Dimi says:

It is a good idea to make 5.9 LTS, because 5.6 is already significantly behind on features. It will be a good idea to stop introducing new bugs and focus on reducing the number of existing ones. Qt has way too many critical and important bugs with zero work done to them for quite a while.

Marek says:

Couldn’t said it better myself. I love new features but amount of bugs is too high. Because of that I had to revert to 5.7.1. 5.8 without patch release is unusable (network regressions) and 5.9 is not ready yet. So for example, using the new Controls 2.1 is not an option.

Kayra says:

I also hope that stability gets a higher priority than feature development.

After the JIRA update, some summary pages got removed. You need to play with filters to get the same information you used to get with summary pages.

I bookmarked the following filters to monitor how Qt development progresses in terms of issues:
Unresolved P0 and P1 issues in released versions (currently 545 issues):

Since I mostly use QtCore and Qtnetwork, Unresolved Core+Network P0 and P1 issues in released versions (currently 43 issues):

A lot if issues for released versions, but Core and Network modules are much more stable compared to the rest of Qt. Probably QtSql is also quite stable but I am not tracking that module.

Kayra says:

I have found the statistics (and activity) view in the new JIRA: After selecting a project, the default view is Issues. Click on the project name or icon at the top left cornet to see Activity view. Then click the “Switch view” drop-down to right of the “Activity” title to change to statistics. Now you can get an overview of the project you are interested in.

By the way the new JIRA is majorly broken if you browse it after logging in. Don’t click around if you are logged in, just log in at the last minute when needed.

Sandro F says:

Very good news! But please please fix following issue to make Qt 5.9 useable at all:


Please give Simon a hint to review that patch.


VojtechT says:

Well, with Qt5.6 having bugs like QTBUG-57468 we still use Qt4.8 for releases. Yes, many new features are introduced, but reliability of Qt goes down…

@VojtechT: QTBUG-57468 is fixed in Qt 5.7.1 and also in 5.9.0 release (as all earlier bug fixes will be part of Qt 5.9). It is also pushed to Qt 5.6 branch and will be included in Qt 5.6.3 patch release when that is released.

VojtechT says:

That is nice, but I need for my customer support for older Mac platforms than Qt5.9 offers. I understand, that you have to move on, but I just can’t understand, why can’t you fix bugs in a version that YOU decided to be LTS. I’m disappointed, sorry.

@VojtechT: Initially an LTS release will receive a lot of bug fixes, including low priority ones. This was done for Qt 5.6 and will be the case for 5.9 as well. After the LTS release enters the ‘strict’ phase focus is in critical bugs. Reason for this is to avoid causing issues – every bug fix also contains a risk of breaking something.

VojtechT says:

I know, I read about phases in the blog post and I understand the risk of introducing another bugs. But you have to have a working version first. And fact is, that I spent a lot of time struggling with several Qt bugs, I was waiting for a March release of Qt 5.6.3, hoping we would start making releases with this version, but it got postponed to August 2017 and instead of it I can see another LTS version coming out. And I still don’t whether any of these will be stable enough…
Don’t take it as I don’t appreciate the work you are doing. But sometimes it complicates things a lot and we will be the ones who will have to explain things to end customers…

Firat says:

I have to agree with VojtechT. There is this Quality impact bug: https://bugreports.qt.io/browse/QTBUG-41170

Even Qt 5.6 LTS did not get that fixed. I wonder when it will ever be fixed. You can’t sell product to a customer if the Application is not look professional. Don’t get me wrong, I ‘m testing Qt 5.9 and it is stable more than every other Qt releases even on Beta. But the fact is, some issues should be prioritized as critical if it is Quality impact.

David says:

Looking ahead to 6.0, can you please give widgets a little love. Your MVC is a a little long in the tooth. Maybe add support for OpenCL. You know, help the user trying to solve big problems that can’t be done in QML or JavaScript. I also vote for a new View class like the recycle viewer found in Andriod for handling large data sets.

Otherwise thanks Qt Company for your great work and keeping it open source.

Slartibart says:

Is there really any scenario that cannot be solved with QML or extensions to QML? Can you please elaborate?

The model objects + friends really need som more advanced helpers and better structure, and as you’ve decided to move to more modern compilers this should be much easier now.

tham says:

I think most of the points are mentioned in “Should you still be using QGraphicsView?” already. Simply put, many things could be done with qml with more or less work around,but why bother when QWidgets and QGraphicsView already do it for you?

qml is a nice tool for embedded, mobile devices, but still far from ideal for those traditional desktop apps, like photoshop, windows offices etc. Please stop your hype of qml.

Alan says:

I am currently using Qt 5.6 LTS, but I am now really looking forward to upgrading to Qt 5.9 LTS. Thanks a lot for all your hard work!

Mihail Naydenov says:

I am stuck in 5.6, because Windows XP is very important for me, so please do not neglect this.

@Mihail: No worries, Windows XP continues to be supported as a deployment target by Qt 5.6 LTS.

Henk Jan says:

What I would like to see is that more bugs are fixed and less bells are added. What do you define with minor bugs during the first half year. Are P2 bug minor bugs?
Many P2 bugs are never fixed……

@Henk: Initially in essence all bug fixes can go in. In the later phases we need to be careful with not pushing too many fixes to cause instability.

Bill87 says:

Dear, have a look toward Qt bugreports. There are thousands of open bugs, still even most peple voted are not being fixed for long time.

Bill87 says:

Do you plan to release TableView in Controls 2 in QML by 5.9/5.10??
And what about including such projects as PureQML into Qt package?

lieefu says:

Looking forward to come true

Qualcuno says:

We are still using Qt 4.8.7 because Qt5 is still not ready for production use. Too many bugs.
Too many problems when compiling static without OpenGL etc.
Every new release something else is broken.

Drew says:

I’m glad (and worried at the same time) to see we’re not the only ones struggling with Qt 5.x. We’ve just recently started to use Qt 5 for deployed packages of our software on Windows, macOS and Linux. At the moment, there is not a single Qt 5.x release available that I could recommend for deployment on these platforms (without applying several patches first).

Having said that, for everyone planning on switching from Qt 4 to Qt 5, Qt 5.6.2 is probably the least broken 5.x release so far.

But unless you really need something that is new in Qt 5, I’d stick with Qt 4.8 for anything that gets deployed to a wider audience using desktop systems.

Kayra says:

For in-house tools which don’t require TLS1.1 or greater, 4.8 is a very good release indeed. Since QtWidgets (QtGui of Qt4) module is “done” with Qt5, Qt 4.8 still is an attractive option for lots of development needs requiring GUI as well.

As for Qt5, I also recommend 5.6.2. In general, regular users, i.e. not early adaptors, should wait until 5.x.2 is released to switch to a new Qt version. If there is no 5.x.2 release, as it was the case for 5.5, 5.7 and 5.8, I would recommend that you stick to the version you are using. I kept using 5.4.2 until 5.6.2 was released. I’ll wait until 5.9.2 is released before considering updating. Since, hopefully, there will be further 5.6.x releases, I’d recommend looking for a concrete reason to update to a newer version instead of updating just for the sake of updating.

Daniel says:

My company made the mistake of jumping from Qt 4.7.2 to 5.0.0 for our commercial Mac and Windows products. 5.0 simply wasn’t release ready.

Since then we’ve moved to 5.2, 5.4.2 and now 5.6.2, primarily for fixes for the multitude of regressions introduced in the 5.x series. Every new version seems to introduce two regressions for every one fix.

I’ve recommended that we stick with 5.6.2 for the foreseeable future because we use QtWidgets and there is literally nothing of relevance to us in 5.7, 5.8 or 5.9.

Digia/the Qt Project seriously need to concentrate more on quality and stability. Qt 4 had it faults but it was solid next to Qt 5. The one feature I would miss going back to Qt 4 is the newer lambda connection syntax.

Fabio says:

Too many bugs unresolved, please slow yourself down ad fix!

tham says:

+1, I guess managers of Digia think new features are more attractive for users compare with bug fixes, but today Qt5 got too many bugs(close to 4000 open issues), Qt team need to focus more on bug fixes rather than implementing new features.

Commenting closed.

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