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[Solved] Will a Qt 4 book be a bad idea.
Will reading a book about Qt 4 in regards to Desktop Apps programming (Widgets) learn me obsolete stuff or
will most still work the same way in 5.5 ?
Nop, that's not a bad idea, especially this one. It's a pretty nice book and it's still valid. You may have to update the examples because of the widgets that got their own module but otherwise go on without regrets.
Super as seems cover most concepts in regards to widgets.