Development versions are early previews of the next production release.
The development version includes the latest features, but may also contain bugs.
Current Development Cycle Release is 6.08.00RC4, released 2019-01-28:
All Other Downloads –
Stable versions are vetted for bugs, and felt to be extremely stable.
The current stable version is 6.06.01, released 2016-07-30. See the release notes for the list of new features.