GTK 4.0 won’t be out this year, nor is it expected next spring as part of the GNOME 3.36 cycle, but now the developers believe this next major tool-kit update will be ready to ship in just over one year’s time with the autumn release of GNOME 3.38…

Source: Phoronix – GTK 4.0 Isn’t Expected To Be Released Until Autumn 2020