Excerpts from Alvaro Cornejo's message of 2021-06-25 18:25:51 -0500:
We also use a VPS provider (Linode) for the koha hosting.
What we do when migrating to a major version is to create a new VPS, install everything from scratch, move the DB from the old system to the new one, do the DB conversion and test that everything goes as expected.
I also use Linode, but I have done a similar upgrade without creating a second VPS and migrating the database. Perhaps that's living a bit dangerously, but it worked for me. I used Linode's backup feature to give me an escape route if something went wrong. Briefly, here's what I did: I shutdown the machine completely, and created a manual backup of the entire machine. After rebooting, I did the upgrade from Debian 8 to Debian 9. This was done using various apt commands. I recall that I had to use Linode's out-of-band ssh service instead of normal ssh at one point, because the upgrade brought down Debian's network service briefly. After the OS upgrade, I made another manual backup of the entire machine. I also made a backup of the Koha database and configuration, and copied those files to my own laptop. Finally, I did the Koha upgrade using the usual 'apt install koha-common'. -- Let's organize this thing and take all the fun out of it. --Ashleigh Brilliant