The requirement is no longer current. It is being updated.

What causes this issue?

You have tried to process a requirement that has been changed by
another user in the meantime and is therefore no longer valid.

System Response

The system updates the requirement.

How to fix this error?

After the system has updated the requirement, you can process it.

Procedure for System Administrators

How can this happen?

You want to schedule requirement 100, item 10. In the meantime, another
user has planned the requirement. The data for the requirement that is
displayed in the planning board is therefore out of date. After you
have confirmed the message, the requirement will be updated in the
planning board. Afterwards you can then process the requirement again.

Error message extract from SAP system. Copyright SAP SE.