Get attachments in Nintex Workflow

I have requirement where I need to get attachments which are added by user by modifying the list item. Every time attachments gets added, wf should trigger-> I could do that using GetAttachments collection and maintaining the count of attachments each time. Only thing I am not able to do is how to attach only those attachments in task notification email which are new. Include attachment checkbox will always add all the attachments in email notification but I want only those attachments which are added while modifying the item.