Trolltech has adopted GPLv3 for cross-platform open source application development toolkit Qt. It is important to note that this is an addition to its availability under GPLv2, meaning it will be available under both licenses. This indicates that even KDE might go GPLv3 in its further releases. GPLv3 raised fair amount of controversy over enforcing releasing the source code. GPLv2 seems to be still more popular, however, toolkits adopting v3 might make it more popular amongst the developers.