Characteristic &1 Conversion routine change to &2

What causes this issue?

The conversion routine for characteristic &V1& has changed to &V2&.

System Response

The existing values for characteristic &V1& have not been modified
correctly. The characteristic therefore cannot be activated if there is
still master data, SIDs, texts or data in DataStore objects for the
characteristic.
This affects the ALPHA, NUMCV, and GJAHR conversion routines. The values
can no longer be found in the tables after the conversion, as values are
not converted automatically.
Other conversion routines can be changed, but this can also be
problematic. You should therefore check manually whether values are
still correct after changing the routine.

How to fix this error?

Undo the change to the conversion routine or delete all master data from
characterstic &V1&.

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.