Issue
You are wondering if there is a maintenance history for your Heroku Key-Value Store database.
Resolution
You can view the most recent maintenance history for your database with the heroku data:maintenances:history command.
This command requires the Heroku CLI and the Data Maintenance CLI Plugin. The plugin can be installed with the below command:
heroku plugins:install @heroku-cli/plugin-data-maintenance
Heroku also sends an email before every maintenance event that you can search for.