Cannot link parent tasks and subtasks when importing issues from CSV in Redmine

When you import parent tasks and subtasks at the same time

(Supported versions: Redmine 4.1 or later / RedMica 1.0 or later)

In Redmine 4.0 or earlier, you cannot import parent tasks and subtasks at the same time. However, you can link them with the following method: register the parent task first, and then import the subtasks.

When you import subtasks under an existing issue as the parent task

If you import a CSV file that specifies the number of the parent issue, you can register subtasks linked to an existing issue.
To specify the parent task, enter "#" followed by the issue number, such as "#100", in the Parent task column. Please register the subtasks after you register the parent task.