GDAL 3.0.0, the final fruit of the GDAL Coordinate System Barn Raising project, is out today. Mapbox, my employer, was a financial supporter of the work and I was the shepherd of that support. I'm very pleased at the results and grateful to Howard, Paul, Kristian, and Even for taking the risk. The value Mapbox gets for a small investment is enormous. Are you an engineer at a company that should be supporting GDAL like this and don't know where to start? I'm happy to share my experience.
Here is Even Rouault's release announcement: https://lists.osgeo.org/pipermail/gdal-dev/2019-May/050202.html. Please take note: 3.0.0 has some big and breaking changes. It is not supported by the latest stable releases of Fiona and Rasterio. If you have installed either of those libraries from source distributions, not wheels, and you upgrade your system GDAL to 3.0.0, your Python programs could be broken. If you've installed Fiona and Rasterio wheels, which include their own copy of GDAL 2.x, you're safe.