REST API plugin won't build under 18.12.08

[Ernest Hocking]

Good morning everyone

I've tried to install the REST API plugin into 18.,12.08.   Running
./gradlew build I get a series of errors similar to:

/home/ernest/ofbiz-18.12.08/plugins/rest-api/src/main/java/org/apache/ofbiz/ws/rs/resources/OFBizServiceResource.java:9
3: error: cannot find symbol
            if (service != null && service.isExport() &&
UtilValidate.isNotEmpty(service.getAction())) {
                                          ^
  symbol:   method isExport()
  location: variable service of type ModelService

in OFBizServiceResource.java I see:

 ModelService service = context.getModelService(serviceName);
            if (service != null && service.isExport() &&
UtilValidate.isNotEmpty(service.getAction())) {

checking the class definition for ModelService  there appears to be no
method definitions for the isExport(), getAction(),isAuth(),getName().....

so it appear that the plugin has not provided these additional methods.

Any help in locating a fix would be appreciated

thanks in advance

Ernest