Question

How is a website backend updated without a shutdown?

Answer 1

It depends. The correct way is:

1. take a backup
2. set site in maintenance more
3. and if the site is small, restore the new version with the new backend from the stage or test site, otherwise if the site is very big substitute the old backend
4. take a backup and test
5. set site online

Of course there are some factors, like if the users use the backend (e.g. for login), if you can partially can upgrade to the new backend and more