Follow EAP 7.3 documentation and configure a JBoss EAP 7.3.1 Domain Controller to Administer a JBoss EAP 7.1.6 Host Controller. An example profile="full-ha-eap71" (as renamed from the "full-ha" profile) can be copied from the EAP 7.1.6 domain.xml and added into EAP 7.3.1 domain.xml, as well as a "full-ha-eap71-sockets" socket-binding-group, and a defined custom server group ("ServerGroup-eap71" with empty assigned servers) Have the EAP 7.3 master host DC and EAP 7.1.6 host slave started Try to add a new server in the server-group with profile copied from the older EAP 7.1.6 host. This will not work and the following error always comes up on CLI started on the EAP 7.3.1 Domain Controller [domain@xx.xx.xx.xx:9990 /] /host=SlaveEAP71/server-config=SlaveJvm-EAP71:add(group=ServerGroup-eap71) { "outcome" => "failed" , "result" => {}, "failure-description" => { "host-failure-descriptions" => { "SlaveEAP71" => "WFLYHC0201: Error synchronizing the host model with the domain controller model with failure : WFLYDC0075: Cannot synchronize the model due to missing extensions: [org.wildfly.extension.microprofile.opentracing-smallrye, org.wildfly.extension.microprofile.config-smallrye, org.wildfly.extension.ee-security]." }}, "rolled-back" => true } [domain@xx.xx.xx.xx:9990 /]

a workaround right now is to add the server manually by editing the host*.xml file and adding the server under the servers section, then start the host as usual: <host name= "SlaveEAP71" xmlns= "urn:jboss:domain:5.0" > ... <servers> <server name= "SlaveJvm-EAP71" group= "ServerGroup-eap71" /> </servers> ... </host> After adding at least one server manually in your host*.xml, then you will be able to use the CLI (or Admin GUI Console) operation to add more servers: [domain@xx.xx.xx.xx:9990 /] /host=SlaveEAP71/server-config=SlaveJvm-EAP72:add(group=ServerGroup-eap71) { "outcome" => "success" , "result" => undefined, "server-groups" => undefined }