What is Upgrade JBoss Remoting?

About JBoss Remoting UpgradeIf you know the outline of how it works, could you please let me know?

Specifically, I was reverse engineering an existing client server system, and I was working on it, so I would like to know what you are doing.

Probably the processing flow is

However, the UpgradeFailedException occurs in the above two.

The reason for this is that we have a proxy between client servers that have never existed before.The proxy is forwarding HTTP only.

I would appreciate it if you could let me know in part what JBoss Remoting is.