Once the 2.14 release has happened, we will branch off a 2.90 branch.
Development towards 2.16 will proceed on trunk, in parallel to the 2.90 development.

The goal is to have a 2.16 release by next summer (traditionally targeting Guadec). The following features are already under development and will likely land in 2.16:

• support for icons in entries
• better handling of invisible characters
• flippable boxes, separators, etc
• resolution independence/font scaling
• complete offscreen window support
• extended layout (width-for-height)
• a tool palette widget
• a simple list api

The 2.90 release will be feature-wise equivalent to 2.16, with structure contents being completely sealed and deprecated 2.x interfaces removed. 2.90 will be installable in parallel with 2.16.

After the 2.16/2.90 releases, GTK+ 2.x will continue to be supported by bug-fix releases on the 2.16 branch, while the 2.90 branch will move ahead with new feature development, leading to a GTK+ 3 release further down the road.

For more details on the work towards 2.90 and beyond, see the GTK+ 3.0 Tasks page. We will also add more GTK+ 3 information to the GTK+ website in the coming weeks.