Greetings!

The foundation has long since stopped using Debian Stretch for new projects, and will start actively removing it from the data centers this summer.

In the meantime, I don't want any one who is on the fence to choose Stretch when they could choose Buster, so I'm removing it by default from the image options in Horizon. If you still need to use it for legacy reasons, feel free to contact a cloud admin or open a phabricator ticket; restoring access to a specific project is simple. I'm also leaving it enabled for the deployment-prep and integration projects as I've no doubt they'll still need to create Stretch VMs until it's fully phased out in production.

-Andrew