XOWA currently releases a version every month. The major versions are for new changes while the minor versions are generally for fixes.
Both versions should be considered stable. Note that XOWA has over 5,000 automated unit tests, and more are added in each release. However, for those who prefer a more conservative update, the major version may be more suitable.
All files are currently released at https://github.com/gnosygnu/xowa/releases/