When will the official update for from Zorin OS 17.3 to Zorin OS 18 be available?
Is there already an exact date for this?
No, there isn't a Date now for the final Release. But if You want, You could use it now in Beta Status if You wish.
Make a BackUp of all Your Files and create a bootable USB Stick. then update Your System. Then open the Terminal and type gsettings set com.zorin.desktop.upgrader show-test-upgrades true and press Enter. Then open the Upgrader.
Thanks Leon,I`ll wait till the official release.