The developers of the library GTK plan at the end of the year to form an experimental branch 4.90, In which the functionality for the future release of GTK5 will develop. Before starting work on the GTK5, in addition to the spring release of the GTK 4.10, it is planned to publish the GTK 4.12 output in the fall, which will include developments related to color management. The GTK5 branch will include changes that violate compatibility at the API level, for example, associated with the transfer of outdated some widgets, such as the old dialogue for selecting files. The possibility of terminating the X11 protocol and abandoning the possibility of working only using the Wayland Protocol.
is also discussed in the GTK5 branch.
From additional plans, one can note the intention to use a more expressive for the development of GTK than the programming language and a more functional compiler than is provided for SI. Which programming language can be used not specified. It is not about the complete rewriting of all GTK components in the new language, but about the desire to experiment with the replacement of small parts of the GTK with implementation in another language. It is assumed that providing the possibility of developing in additional languages will allow you to attract new participants to work on GTK.