The point of maintaining the QML 2 engine is - to still support live preview/editing of QML components,
- giving users the choice to actually have all of the power of JavaScript, including closures, generators, the arguments object, etc., in their QML components, - to not break thousands upon thousands of lines of existing QML 2 code for people migrating from Qt 5 to QT 6 - and to have a JavaScript engine which at some point can finally send QtScript into retirement The reason for having QML 3 (as a strict subset of QML 2) is that by adding some restrictions to QML we can significantly enhance the tooling, and also make it possible to compile it to C++ for greater performance. The whole discussion about the QML execution engine doesn't however preclude changes to core QtQuick and QtQuick.Controls 2 (which is what Giuseppe was referring to), though the guiding principle here is still to break as few code as possible. Kind regards, Fabian Am 11.11.19 um 19:36 schrieb Kevin Kofler: > [...] > Then what's the point of maintaining the whole old version, if it won't be > compatible anyway? > -- -- Fabian Kosmale Software Engineer The Qt Company GmbH Erich-Thilo-Str. 10 D-12489 Berlin fabian.kosm...@qt.io http://qt.io Geschäftsführer: Mika Pälsi, Juha Varelius, Mika Harjuaho Sitz der Gesellschaft: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB 144331 B -- _______________________________________________ Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development