Racket version 5.3.1 is now available from

  http://racket-lang.org/

Racket:

* The `case' form dispatches on characters, fixnums, symbols, and
  keywords in logarithmic time.  (Thanks to Jon Zeppieri.)

* The new `racket/format' library provides new and improved
  string-formatting functions.

* Logging tools include improved filtering support based on the name
  of a logger.  A new `define-logger' form simplifies the use of
  named loggers.  Forms such as `log-debug' now support string
  formatting.

* The `for' forms now support `#:break' and `#:final' clauses.

* The new PLTCOMPILEDROOTS environment variable configures the
  search path for compiled bytecode.

DrRacket:

* Check Syntax now summarizes the documentation (i.e., the blue
  boxes) for the identifier at the insertion point in the top-right
  corner of the definitions window.

* Check Syntax now runs continuously for programs that declare their
  language within the source.  This mode has been available for
  several of the past releases, but now enabled by default.

* DrRacket can spell-check string constants (enable this in the Edit
  menu).

Typed Racket:

* Typed Racket interprets the `Any' type as a different contract.
  This may signal dynamic errors in some existing mixed
  typed/untyped programs.  The normal fix is to replace a use of
  `Any' with a more specific types.

* NaN is included in all of Typed Racket's floating-point types,
  which makes precise floating-point types easier to use.

* Typed Racket supports a `cast' operation with support for
  higher-order types.

* Typed Racket provides the `:query-type/args' and
  `:query-type/result' utilities to explore types at the REPL.

Miscellaneous:

* The `compatibility' collection provides features from Racket
  relatives, such as `defmacro' and mutable lists.  These features
  are provided to ease porting code to Racket.  Avoid them in modern
  Racket code.

* Screenshots of the widgets provided by the Racket GUI library are
  included in the documentation.  (Thanks to Diogo F. S. Ramos.)

* FrTime was ported to racket `#lang'.  (Thanks to Patrick Mahoney.)

Deprecation:

The following has been deprecated and will be removed in the January
2013 release:

* the `planet' command-line tool; use `raco planet' instead.

The following has been deprecated and will be removed in the August
2013 release:

* the `mzlib/class100' library; use `racket/class' instead.