The SDK contains sample code and API documentation. Some of them have not changed since v2016 so still should be possible to use. However, they are not supported officially. So, if you have any issue or error it must be reproducible in a currently supported version (2020.x). We recommend that you subscribe to our Developer Partner Program which includes a full license of the current version for development purposes and technical support by email. The minimum fee is $350 for the first year and $250 to renew in the following years. If you are interested, please send your contact details (business name, address, phone number) to [email protected]. Thank you!