A new API version of Azure Time Series Insights Gen2 (2020-07-31) was made generally available on July 16, 2020, and uses an updated Time Series Expression Syntax (TSX).
The preview API version (2018-11-01-preview) is retiring but will continue to be supported until October 31, 2020.
Recommended action
Migrate your environment's Time Series Model variables, saved queries, and Power BI queries, along with any custom tools making calls to the API endpoints, to the new API version before October 31, 2020. Review the migration steps.
If you have any questions, submit a support request via the Azure portal or ask a question on Microsoft Q&A.