XCF has been GIMP’s primary project format since 1997, and it has served many users well. Over time however, we’ve observed more and more limitations of the binary XCF format. Among other issues, it does not easily support very large or complex projects, such as the multi-page and animation features currently planned for GIMP 3.6.

The new project file format will follow a more common “zipped XML” structure. While the technical details are still being designed and implemented, this change will allow for faster saving since we’ll only need to update parts of the file instead of the whole thing each time. It will also set the stage for much desired features such as auto-saving, which will now be much more feasible.

Non destructive layer masks are also a great feature. PSD support improvements.