How to delete Release/Cycle from a 'Project'?

For the Release/Cycle that you want to delete, click on the Archive button under the Action column.

The Release/Cycle is archived after confirmation. Once the Release/Cycle is archived, you can not edit it.

Note: If a Release is archived, then all the Cycles under the Release are also archived.

The Action column now shows Unarchive and Delete buttons for archived Release/Cycle.

To delete the Release/Cycle, click on the Delete button. The Release/Cycle should be archived first to delete it.

To unarchive the Release/Cycle, click on the Unarchive button.