This release adds two experimental properties to the Products Scroll API. On the server-side, the Scroll API has been enhanced to use snapshots, a faster way to iterate over catalog content. With this newer version, one can now pass the page size and allow to switch back to the older v1 version with the version property. Notice that you shouldn't use these settings unless you know what you do.
From the perspective of the client, the Scroll API didn't change at all. You still pass a page token to get the next slice of results until the server responds with an empty page token. If possible, the server will use snapshots; otherwise, it'll use the older version to scroll through the results.