Would a Trellis upgrade process be within the scope of the Trellis docs? I know upgrading Trellis projects kind of depends on the way you have your project set up and your project requirements, but it took quite a bit of fumbling and confusion through discourse before we had an upgrade procedure set because it’s not documented. The recommendation of using a Digital Ocean floating IP to allow no-downtime switches between environments was also a life saver in our case, as we service websites for customers who manage their own DNS and, how do I put this, don’t always have their finger on the pulse of their domain management logins.
I’d be happy to draft something on our setup based on @fullyint’s process here if that’s helpful, but I’m not 100% sure that we’re following upgrade best practice (e.g. we use Trellis as a git subtree in our projects to simplify the upgrade / merge process).