CTesK 2.1 has been released. The new version contains an installation tool, libraries for work under Cygwin and two additional static reports, intended to represent information about coverage of testing of systems with deferred reactions. Wizards for creation mediators and test scenarios are available in a new CTesK add-in for Microsoft Visual Studio 6.0. The code generated by CTesK 2.1 complies with the C89 standard and gcc compiler of version 2.95.3.