Issue
I have a Heroku Connect add-on that uses the danketsu plan, and I'm not sure what that is.
Resolution
danketsu is the former name of the Heroku Connect paid plan. danketsu add-ons are still fully functional, but as of July 19, 2018, they can no longer be created. Instead, the new name of the Heroku Connect paid plan is enterprise. If your team has purchased Heroku Connect, you'll be able to provision the enterprise plan by selecting it in the Heroku Dashboard add-on UI or by using the heroku addons:create herokuconnect:enterprise CLI command. You can read more about the available Heroku Connect plans in the Dev Center.