http://www-306.ibm.com/software/data/informix/tools/csdk/csdk_280.html
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Technical Detail

The latest release of Informix CSDK 2.81 includes the following features:

A new .Net provider with exceptional data access performance improvement and unicode support for Microsoft® .Net applications that require data access in a variety of locations and formats.


A newly re-architected OLE DB provider with solid data access performance improvement and unicode support for Microsoft® Visual Basic or Visual C++ applications that require data access in a variety of locations and formats.


An enhanced unicode-enabled, industry-standard compliant ODBC driver that enables developers to dynamically access a broad range of Informix database servers including IDS, XPS, Online Extended and Standard Engine.


ODBC and OLE DB API support enabling .NET applications to access IDS server via Visual Studio .NET bridge for ODBC/OLEDB.