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
}
        if (tracerLog.isTraceEnabled() && shouldTraceAction(action)) {
            tracerLog.trace("[{}][{}] received request", requestId, action);
        }
        messageListener.onRequestReceived(requestId, action);
    }
    
    @Override
    public void onRequestSent(
        DiscoveryNode node,
        long requestId,
        String action,
        TransportRequest request,
        TransportRequestOptions options
    ) {
        if (tracerLog.isTraceEnabled() && shouldTraceAction(action)) {
            tracerLog.trace("[{}][{}] sent to [{}] (timeout: [{}])", requestId, action, node, options.timeout());
        }
        messageListener.onRequestSent(node, requestId, action, request, options);
    }
    @Override
    @SuppressWarnings("rawtypes")
    public void onResponseReceived(long requestId, Transport.ResponseContext holder) {
        if (holder == null) {
            checkForTimeout(requestId);
        } else if (tracerLog.isTraceEnabled() && shouldTraceAction(holder.action())) {
            tracerLog.trace("[{}][{}] received response from [{}]", requestId, holder.action(), holder.connection().getNode());
        }
        messageListener.onResponseReceived(requestId, holder);
    }