Only data for the last 30 days is available in Studio or through the API. Our cloud service is not designed to act as a source for data science, or as a backup, for platform partners. Having access to the last 30 days of data is a valuable convenience during installation, for simple use cases, and in case of brief integration issues.
If you are using a platform provider, please contact them to understand how they handle historical data. Many platform providers save all sensor data forever.
If you are a platform provider, please see the DT Developer Docs on multiple guides on integrating with different cloud vendors.