There is also: 3. A toolchain is stable if it has LTS releases and bugfixes are backported to them, regardless of how many changes each non-LTS release brings.

There is also: 3. A toolchain is stable if it has LTS releases and bugfixes are backported to them, regardless of how many changes each non-LTS release brings. But I'm not sure if people think about stability like that often. I wish they did.