retrieve data updates from server without Node.JS

Is it possible to refresh the data on a scheduler by re-fetching a block of XML containing event data on a periodic basis, without using Node.JS?

Sure, you can clear old values and invoke reloading the data via API
docs.dhtmlx.com/scheduler/api__s … arall.html
docs.dhtmlx.com/scheduler/api__s … _load.html
You can easily call it from setInterval. Though probably you’d want to add some checking before refreshing the data in order not to clear calendar while user is resizing or editing one of events