New segment & does not have to be a mandatory segment

What causes this issue?

Segment &v1& is not in the predecessor. It is, however, a mandatory
segment.
Newly added segments are not allowed to be mandatory segments, however,
in order to ensure compatibility with the predecessors.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.