Legacy collections are those collections created prior to the introduction of sampleFormat field. Before the field, we had read signed and unsigned integers as unsigned. To preserve backwards compatibility, we still read integers from these collections in this way, but you can change this by setting sampleFormat. If you do set it to INT, do note that you will get integers as signed in evalscripts from then on, and that you can set the field only once. Until you set it, we don’t require that the formats in BYOC and files match.
The format can be set in Dashboard or using API. Check here how to set it using API. Using Dashboard, click edit button, which is marked with a red rectangle in the screenshot.
