The exact way Hisense’s support team works with serial numbers for updates might not be public knowledge, and it could change.
But usually, customer support teams have steps in place to deal with specific problems, especially when it comes to fixing or updating serial numbers for updates.
When you provide them with your TV’s serial number, they go to their website’s database and add your TV’s serial number as a new record.
So, we can surely say that they do this manually.
Just have your purchase proof and TV info ready when you talk to them for a smoother fix.
Hope it helps…