There's currently a check in `TransportService.HandshakeResponse.isIncompatibleBuild` to stop ES with the same Version but different build hashes from joining a cluster. This needs to be relaxed for cloud deployments where Version is not applicable
server/src/main/java/org/elasticsearch/transport/TransportService.java
final DiscoveryNode localNode;
        private final String action;
        private final long requestId;
        final TransportService service;
        final ThreadPool threadPool;
        DirectResponseChannel(DiscoveryNode localNode, String action, long requestId, TransportService service, ThreadPool threadPool) {
            this.localNode = localNode;
            this.action = action;
            this.requestId = requestId;
            this.service = service;
            this.threadPool = threadPool;
        }
        @Override
        public String getProfileName() {
            return DIRECT_RESPONSE_PROFILE;
        }
        @Override
        public void sendResponse(TransportResponse response) throws IOException {
            try {
                service.onResponseSent(requestId, action, response);
                try (var shutdownBlock = service.pendingDirectHandlers.withRef()) {
                    if (shutdownBlock == null) {
                        
                        return;
                    }
                    final TransportResponseHandler<?> handler = service.responseHandlers.onResponseReceived(requestId, service);
                    if (handler == null) {
                        
                        return;