From any EWS clients perspective there is nothing to support in regards to hybrid mode. What's important is the Endpoint (exchangeservice.url) you submit to.
So what is import in regards to a hybrid setup is that your using Autodiscover and that Autodiscover is configured correctly for Hybrid mode. Outlook use EWS for FreeBusy/Out of office so if Autodiscover is configured correctly and your Outlook clients work
okay in Hybrid mode then you shouldn't have an issue with any other EWS client as long as you use AutoDiscover as this will be same endpoint.
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