The latest Debian version, 10.0 "buster", was officially released a few days ago[0].  Today, I've built a new Debian buster base image and made it available in all projects.

The Stretch base image will remain available for some time to permit compatibility with existing setups, but any new work should use buster.  If you have existing instances that were built using the buster prelease images (or instances that you manually upgraded from an earlier version) I encourage you to delete them and rebuild with this new base image for the most consistent results.

-Andrew