Since this update required some manual intervention anyway to update the database version, I took the opportunity to perform some overdue server maintenance and upgrades.
I have migrated the server to a more powerful configuration, and changed the way image files are being stored and served (object storage as opposed to filesystem storage).
I am also aware of some federation issues that have affected this and other instances. I am not sure whether this upgrade will deal with these problems automatically. I will be looking into it and hopefully will implement some solution soon.
Sorry for the downtime experienced in the past few days, but hopefully with the more powerful server the experience will be smoother and will remain so for a while.
For other admins and users interested, this is a bit of information about the server
The 400 GB SSD was being used to store both the server's database and the image files, and this component in isolation had a monthly cost of $36. I have migrated the images to an object storage provider ($6/month for 500 GB), and used the resources previously used for disk space to increase
the other parameters. The new configuration is a lot better and less expensive.