http://plt-scheme.org/

* DrScheme changes:

  - The Module language now has an automatically inserted `#lang'
    declaration, so the interactions window is available right
    away for new windows.

  - Searching is now interactive (see the manual for details).

  - Memory limits are now enabled by default.

* Typed Scheme supports a novel type checking mechanism for
  homogeneous and heterogeneous variable-arity function
  definitions and applications.

* Redex (a domain-specific language for testing operational
  semantics) is now included in the distribution. See also
  http://redex.plt-scheme.org/.

* Lots of improvement to the documentation, including: better
  searching, table-of-contents, and language-sensitive help (in
  the teaching languages).

* The world.ss teachpack no longer supports `end-of-time', only
  `stop-when'.

* MzScheme has now a logging facility, search the documentation
  for "logger" for more details.

* Bug fixes:

  - `begin' in R5RS (and derived languages),

  - `#lang planet',

  - `eval' works with phases.