This is the first release of the 4.x branch, major new features include:
Integration with the larger community JIRA PHP API
Using config entities to create multiple JIRA endpoints
While this is considered a beta, it should work for most use cases. Before a full release we'd want various users to test out this version and verify the config entities are working as expected.
This is a small release that makes some code improvements and enforces the key module as dependency. No additional features are included in this release.