Currently, Jira Software Cloud provides a REST API to delete boards. We will soon be removing the ability to do this from team-managed (fka next-gen) projects. The API will remain unchanged for company-managed (fka classic) projects.
Jira Software only supports one board per team-managed project.
The removal of the ability to delete a team-managed project board will protect against situations where projects are impaired since there is no way to restore the board or create a new one.
Ensure that your apps are not using the DELETE board API for team-managed projects.
Because this is related to a HOT incident, this change will be rolled out no sooner than 17th June, 2021.