As you could see from the image above. The issue is that the system creates a generated number for drafts while the document haven’t been submitted yet, therefore, the number of the draft is the same as the submitted document. This lead to the problem in case user1 creates a document 001 and user2 creates a document 002 as drafts, so if user 2 submit the document before user1, the document number of user2 will still be 002, though, it was posted before document 001.
I couldn’t find the feature that is mentioned in the PR in erpnext version 13, so do I have to upgrade to version 14?
PR is still open. It hasn’t yet been merged.