The “test a new version” feature will create a new snapshot for your page. The previous snapshot and data will be stored as a saved snapshot, and all new data that is collected will be added to a new snapshot.
The “update this snapshot” feature allows you to update the image of the screenshot we have for your page. This is useful for blogs or sites that have made minor changes and still want data to accumulate on the same snapshot. The image will be updated and all previous data will be placed against the new image.