There is a couple of pages on their support site you can subscribe to:
General Release notes overview page:
Release notes by Product (Only notifies for new products):
From mid April they started doing a date based release note so you could actually get an update when stuff was happening:
And then there is the product specifics:
Web, includes API, backend stuff and the web based client:
One thing to note is that EU release is about 1 week behind the official release.
Finally there is the incident page https://status.zoom.us which mostly will give you alarms
for stuff that does not concern us. But that is a statuspage.io site with the inherent options for subscriptions.