I spent about 12 hours to get a Rails 5 application, recently upgraded to Rails 8, to deploy to a new virtual private server, or vps. While the application ran fine on my local development machine, it did not run at all on the new production vps. Turns out that when you run the rails app:update tool it doesn't add all the new helper scripts and configuration files. It just adds some of them. I spent the last 12 hours figuring out what was missing, what needed to be updated, and what needed to be removed. Later today I will add a list of the files here. Right now I need to get some sleep.