Google has updated its site move and domain migrations help document to note that for domain migrations, you should make sure to submit Change of Address requests for all domain variations. Google said the "domain migrations work best when all variants of a site are migrated properly."
Google added a new blue box that reads:
For domain migrations: If you're moving your site from one domain to another, make sure to submit Change of Address requests for all subdomains and the www and non-www variants of the old domain name (for example, from en.example.com, www.example.com, and example.com to new-example.net), even if you're not actively using these variants. Ensure that you have all of these variants verified in Search Console.
"The site move guide now includes information on using the Change of Address tool for all subdomain variants (including www and non-www) during domain migrations," Google explained.
I don't think this is something new, technically in how the Change of Address tool works, but rather Google clarified this in the document. But I am not sure.
Here is a screenshot of what was added:
Forum discussion at X.
