private boolean newerVersion(SearchChain searchChain, SourceGroup sourceGroup) {
            if (searchChain == null || sourceGroup == null) return false;
            return newerVersion(searchChain.getComponentId(), sourceGroup.getComponentId());
        }
Returns true if searchChain.id newer than sourceGroup.id
config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/FederationSearcher.java