DBCHQE is called by a CLIv2 application to obtain information about its execution environment. When used by an application supporting multiple releases of CLIv2, TDP, or Teradata Database, some return codes that indicate downlevel versions of these components must be handled by the application, most often as equivalent to the information not being available.
For queries that return collections of items (Aggregate‑support‑list, Procedure‑data, and Utility‑data), these applications should also allow for downlevel versions of CLIv2 by ensuring that items of interest are present by checking the returned length (QEPRALEN).