Qt Company closes Qt 5.15 source code after commercial LTS release appears

Qt Company closes Qt 5.15 branches for new commits from open source developers. The shutdown coincides with the release of Qt 5.15 LTS, a release that will only be available to paying users of the application framework.

The commercial LTS phase of Qt 5.15 has been announced by Tuukka Turunen of Qt Company. “All existing 5.15 branches remain publicly visible, but they are closed to new commits,” he reports. Qt Company thus becomes responsible for further patches for Qt 5.15 LTS. That first Qt 5.15.3 LTS patch is scheduled for February and will therefore only be available to paying users.

Qt is a cross-platform application framework and users can use the toolkit to develop interfaces and apps for Android, Linux, macOS and Windows, among others. The software has its origins in Norway, where the development was started by Trolltech in the early 1990s. In 2008 Nokia acquired Qt, but in 2012 Nokia divested it again. Since 2014, Qt has been part of Qt Company.

Even non-paying open source developers can access Qt 6.0. That next release of Qt 6.0 has been available since December, though support for most Qt 5.15 add-on modules won’t come until the release of Qt 6.2, as The Register notes. Qt 6.0 requires a compiler that is compatible with C++ 17 and includes a new graphics architecture that relies less on OpenGL and uses Direct3D on Windows and Metal on macOS by default.

Open source developers are critical of the plans, as Qt 6.0 does not yet support many add-ons and Qt 5.13 and Qt 5.14 are no longer supported, posing security risks. A few are discussing the possibility of a fork of the 5.15 release, though it’s not clear whether those plans are feasible or allowed by Qt Company.

That company announced last year that it would make Qt’s LTS releases available exclusively to commercial users. The reason, according to the company, is that revenue is needed to keep Qt stable for long periods of time and add new features, something that Qt says will also benefit open source developers.

Update, Thursday, 10:30Qt Company has offered open source developers access to third-party module maintainers from the commercial repositories, but at least Intel software architect Thiago Macieira reports that there is no interest in doing so.