Incrementally Refreshing Source Data

You can set up prepared sources for incremental refresh. Raw sources are always setup for full refresh while prepared sources can be set to full refresh (default) or incremental refresh. You can now set up prepared sources (based on one or more columns) for incremental refreshes. You have the option to (Keep Original) or (Replace Original) for any matching values in existing rows in the prepared source.

Then select the Incremental tab and select your criteria.