Safely Update from 8.2.1 to latest version?
Looks like a manual update is required.
Should I update to the latest version or take an interim step(s)? The site uses Express quite heavily and I'd hate to cause error with it.
Instead, download a zipped up copy of the file system and export your database to your PC.
Install a local server on your PC and recreate your site on the local server using your downloaded files and database.
For a windows 10 PC try WAMP. For a MAC PC try MAMP.
There are several other local server flavours available a Google search will throw up plenty of options.