The Diligent Engine just released version 2.4. The Diligent Engine is an open source cross platform rendering library that abstracts away the details of working with underlying technologies such as Direct3D, OpenGL and Vulkan. The Diligent Engine is open source under the Apache 2.0 license and is available on GitHub.
Details of the release:
You can get more details of the release in the release notes available here. We recently did a hands-on video of the Diligent Engine in action available below.