The GNU Image Manipulation Program introduced optional single-window mode in version 2.8, which was released on May 3, 2012. It was made default starting with version 2.10, which was released on April 27, 2018.
Here’s what warrants a major version bump: GIMP 3.0.
Yes, it’s because it keeps track on object lifetimes and data access when sharing objects, even across threads. It means that once things compiles a whole category of common and often difficult to debug errors are gone. It means much less time debugging and fewer issues once in the hands of the end user. There can still be bugs but it’s more about logical errors than difficult memory issues.
As a C++ dev for 20 years, I love Rust. Humans are fallible, even if endeavouring to use safe patterns. Might as well just let the compiler use some CPU cycles on that.