No new version created because a message has not yet been transmitted

What causes this issue?

You have changed a print-relevant field. However, the system will not
generate a new version containing these changes.
A new version can only be created if all existing messages have been
printed.

How to fix this error?

If you would nevertheless like to have a new version created, proceed
as follows:
Choose "F12=Cancel".
Go to transaction ME9F and print out all not-yet-processed messages.
Change the print-relevant field in the purchase order again. A new
version will be created.

Procedure for System Administrators

Define the corresponding attribute (either 'W' for Warning or 'E' for
Error) of system message MEDCM027 in Customizing (MM -> Purchasing ->
Environment Data -> Define Attributes of System Messages).

Error message extract from SAP system. Copyright SAP SE.