@Jo279 Yes, I posted about this a couple weeks ago. It's so frustrating that they change things without giving instructions regarding the change. I also have to email all my guests a map to my place, as it's hard to find.
Go to the guest's reservation. Scroll down the page. There is a line that says "Email". Right click on that, click on "copy link". Then go to your email, to compose a new email, and in the address bar right click again on "paste". The guest's coded email address will appear in the address bar.
This is the way I've done it, anyway. There may be other ways.