GIMP 2.10 will be released later this year, and is set to be the next major release of the image editor. Based on the current 2.10 changelog (and features in the development versions) it’ll ship with a tonne of changes.
First off the big one: the editor will rely entirely on the Generic Graphics Library (GEGL) ‘for all operations.’ GEGL work has been ongoing for many years, and is summarised and explained by better writers than me elsewhere on the web. Suffice to say: it’s a big change, but one that will improves the accuracy, precision and editing capabilities of the app.