Current segment definition & can still be changed

What causes this issue?

The current segment definition &v1& is not yet released and can
therefore still be changed.

System Response

You can change segment definition &v1&, but cannot add any further
segment definitions yet.
This is not possible until segment definition &v1& is released.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.