Hi!
I has passed quite long since I started JS8CALL, but it is based on wsjt-x source and should work with same wsjt-remote.

Well, started my js8cal and it seems to be 2.2.0 version.
After setting reporting/UDP 239.255.0.0 / 2237 (that is an UDP multicast address I have also in Cqrlog settings wsjtx-remote says (on top of cqllsign column) "Not wsjtx msg!"

For some years back it used to work. That was what I was thinking...
How ever decided to open Cqrlog/Help and see what I was written there. And, yes. It was not wsjtx-remote at all.
I have bad memory...
THIS SHOWS HOW IMPORTANT IT IS TO READ HELP !

With Js8CALL, as well as N1MM, the remote is called "remote mode for ADIF" (ctrl+K or NewQSO/File/remote mode for ADIF)
After checked preferences/fldigi wsjt interface/ADIF port and ADIF address to be 127.0.0.1 and 2237 I entered the same to Js8CAll/settings/reporting/UDP server address and port and enabled UDP server API and enabled UDP requests.

Then started remote with ctrl+K and logged a fake qso in js8call log sheet. It takes few seconds to appear to Cqrlog, but it works!