According to Wikipedia, Qt was open source since Qt 2.0 with QPL and in Qt 2.2 it was released under GPL because their custom QPL was not compatible with GPL. T

According to Wikipedia, Qt was open source since Qt 2.0 with QPL and in Qt 2.2 it was released under GPL because their custom QPL was not compatible with GPL. This was in 2000, so during KDE2 times (KDE3 was released in 2002). AFAICT technically it was only KDE1 that relied on non-opensource Qt.