It's not the navigation that requires the server but the processing of the mapping data. Which in itself is BS because most of these vacuums come with hardware roughly equivalent of a top of the line smartphone from about 5-6 years ago. They can easily do the raw data to map conversion, even if it's a bit slow and takes 20-30 seconds. Also if you read the article it specifies that the damn thing is already running Google Cartographer which is a SLAM 3D map builder software - one of the better pro-grade mapping software suites, mind you. So the whole claim of cloud needed for processing is BS.