I don't think so. Delta Chat seems a system running 'Chat over ICMP', so CoI goes on protocol layer, while Delta Chat goes on application layer.
Where do you see that Delta Chat uses ICMP ?
LOL. My bad. Its Chat over IMAP.
It sounds like CoI took (tempted to say hijacked) a subset of Delta Chat (protocol subset), something that was already shipping and working, and merely rebranded it.
Delta Chat is just a CoI client, as CoI webpage says.
"Thanks to Delta Chat Core, as a client developer you do not even need to deal with IMAP directly."
https://www.coi-dev.org/