As Salesforce Files of Archived Activities are not displaying in Lightning, our Sales manager is asked to try an option. That is to move the Files attached to Task/Events to its associated Opportunity or Account after a year or certain time period. I was thinking if we can update the Parent ID of Content Document to ID of Oppr/Acc. But am facing some issues trying that. So is that even possible? Any ideas?
You need to insert a contentDocumentLink record. As files can be connected to multiple records, you can simply insert this and the file will be connected to both. This assumes you are using file and not attachment.