Major New Features:
- There is now a macro rewriting system (
http://code.google.com/p/cat-language/wiki/Macros ) called MetaCat
based on Manfred von Thun's paper "A Rewriting System for Joy". This
system can be used for optimization and to express the semantics of
the rest of the Cat language.
- There is a CIL compiler (
http://code.google.com/p/cat-language/wiki/Compilation )
- The type checker and type inference algorithm now works for most
simple expressions with non-recursive types (type_of and #t)
- New optimization tools include a sub-expression evaluator (
http://code.google.com/p/cat-language/wiki/PartialEvaluation )  and
inline function expansion (
http://code.google.com/p/cat-language/wiki/InlineExpansion )

Minor changes:
- qv is now quote, and eval is now apply.
- the help meta-commands (#help and #h) is now more descriptive

Documentation:
There have been significant changes to the online documentation of the
primitives list ( http://www.cat-language.com/primitives.html ), now
there are nearly 250 documented primitives. The specification has also
been updated ( http://www.cat-language.com/manual.html ).

I'd love to hear your comments, suggestions or request.