In the old version of the system, you could only connect one job /sales order to one quote or one invoice to one job. With the new version, you can link multiple quotes, jobs, invoices, etc. together. You can even link quotes or invoices together.
This means that the old tabs at the bottom of the edit screen are gone and have been replaced by one tab ‘Links & Associations’.
If you want to associate a document to another one, use this new tab instead of the old singular link functionality.
It’s a big change and there will be a few more releases to get more from its potential. The PO list screen used to show the associated job or quote. This will be reinstated in phase 2 of this release in the next week or two.