No metadata upload since upgrade

What causes this issue?

DataSource replication has not been performed since the source system up
grade&V1&.

System Response

The Content that is assigned to this source system is obsolete.

How to fix this error?

Refresh the metadata completely for this source system.

Procedure for System Administrators

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.