In meanwhile I found out that same id as a field would be sufficient to prevent duplicate 

For polling triggers the id field in each object from your API governs deduplication. Zapier won’t process the the same ID twice while the Zap is enabled. That last part’s important to know about. The “deplication database” is rebuilt each time a Zap is enabled. In other words if a Zap is paused, and 12 new items were added, those 12 items would not be handled. They’d be added to the dedup database and only new items found after that inital poll request would be processed by the Zap. 

If you’re changing an endpoint, make sure the change is non-breaking to ensure your users’ continuity: Same auth, same trigger and action key names, say existing set of input field key names and types, no new required fields, and the same output, etc. With non-breaking changes you’ll be able to migrate users’s Zaps to the new version of your integration without interruption. 

thanks for detailed response