As you can imagine, GTK 4.0 is a massive update and a huge milestone for the development of the open-source and cross-platform GTK widget toolkit, which is used for creating graphical user interfaces, also known as GUIs, for Linux apps. GTK is mostly used by the GNOME Project for the GNOME desktop environment and related apps. GTK was previous referred to as GTK+, but with this release the + was dropped and the toolkit’s name is now simply GTK. GTK 4.0 is the future of the toolkit, enabling application developers to build astonishing graphical user interfaces for GTK apps, as well as the next major version of the GNOME desktop environment.