Before XCO 3.2.0 release, Host Authentication service runs on the XCO host with its own certificate with an expiry of 10 years. This certificate had no renewal procedure.
The Host Authentication service runs on port 8079. The port is closed from external access. This service reuses the XCO server certificate on 443 with an expiry of 3 years.
Important
From XCO 3.2.0, the Host Authentication Certificate is not present anymore. You can use the XCO server certificate.