Along with other limitations such as "we do not support IPv6 floating IPs. All floating IPs are IPv4" and "floating IPs do not support SMTP traffic"
It's probably a failure of imagination on my part that I can't think of a use case where I would want that.
Why not just use normal, forward DNS?
"Set up valid reverse DNS records of your IP addresses that point to your domain."
Couldn't you just reformat with what ever OS you want?
https://www.digitalocean.com/docs/droplets/how-to/rebuild/
I thought support could help me out given the CentOS situation and it being a special case but they weren't even aware of what was happening or that users would need to move off despite my explanation in the ticket. Hopefully it's better now it's more widely known.
This line in the documentation might be misleading. Unless you have a very old legacy droplet that uses HV-assigned kernels, you should be able to reimage your droplet and use another OS.