I’ve got a project that has two different custom domains attached to it. Let’s say old.com and new.com. Currently the primary domain is old.com and some branch subdomains are created, like staging.old.com and they are actively used.
Now if I want to change the primary domain to be new.com, so future branch subdomains will use that domain instead. How will I keep my old branch subdomains active, so the transition can happen over time?
If I setup Automatic deploy subdomains with new.com, and switch over the primary domain as well. Will the old branch subdomains remain pointing do old.com? Or will they switch over to new.com as well?