Chapter https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.4/html/development_guide/clustering_in_web_applications#clustered_ha_singleton_service in EAP 7 documentation still references classes that were removed in https://github.com/wildfly/quickstart/pull/530/;

At present there is no development guide for EAP 8 in https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/8-beta;

In case it will be produced for EAP 8, the "HA Singleton Service" chapter needs to be updated to reflect the changes in the "ha-singleton-service" quickstart