Upgrading QuickBooks

Will the sync still work, after I upgrade QuickBooks Desktop?

TO DO QB creates a back up

TO DO what happens to my settings in Connex? Are they stored on my local computer or on the web?

TO DO: How to get a new pairing file, if I can't find the pairing file in my web connector?

TO DO How do I update my company file path?

If file is open, the sync is fine.