You may not use delta version &

What causes this issue?

Version &V1& in controlling area &V2& is a delta version, since a
<DS:DE.REFVS>reference_version</> is maintained for it.

System Response

Version &V1& cannot be used as a model or a target version when copying
planning.

How to fix this error?

Please enter another version.

Error message extract from SAP system. Copyright SAP SE.