As of 15.2, iMIS requires that all tables be fully ANSI compliant, so they must be created with SET ANSI_NULLS ON and SET ANSI_PADDING ON. During upgrades, the ConvertTablesToANSI command-line utility rebuilds every table in the database that is not ANSI compliant, including user-defined and third-party tables. See ANSI Conversion Utility - ConvertTableToANSI for details.
If you are creating your own tables, procedures, triggers, views, etc., be sure to set these ANSI settings:
SET ANSI_DEFAULTS ON
SET IMPLICIT_TRANSACTIONS OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF