The stable (release) versions have even minor version numbers, while the development versions have odd ones. So, for example, 1.10.5 is a stable version, while the 1.11.9 is the development version.
The stable versions only receive bug fixes after being released, while the development versions get new features, fixes, and, perhaps, bugs, and are meant for people with a tolerance for that.
There is support for one release branch; so, when the 1.10 release is available (and a new 1.11 development series start), no more changes are expected for the 1.8 releases.