Release Announcement for Version 7.5

Racket v7.5

Racket version 7.5 is now available from

* Almost all of Racket version 7.5 is distributed under a new,
  less-restrictive license: either the Apache 2.0 license or the MIT
  license. See
  for more details.

* Racket CS remains "beta" quality for the v7.5 release, but its
  compatibility and performance continue to improve. We expect that it
  will be ready for production use by the next release. We encourage you
  to check how well the v7.5 CS release works for your programs, and
  help push the project forward by reporting any problems that you find.

* The Web Server provides a standard JSON MIME type, including a
  response/jsexpr form for HTTP responses bearing JSON.

* GNU MPFR operations run about 3x faster.

* Typed Racket supports definitions of new struct type properties and
  type checks uses of existing struct type properties in struct
  definitions. Previously, these uses were ignored by the type checker,
  so type errors there may have been hidden.

* The performance bug in v7.4’s big-bang has been repaired.

* DrRacket supports Dark Mode for interface elements.

* Plot can display parametric 3d surfaces.

* Redex supports modeless judgment forms.

* MacOS 10.15 (Catalina) includes a new requirement that executables be
  "notarized", to give Apple the ability to prevent certain kinds of
  malware. In this release, all of the disk images (.dmg's) are
  notarized, along with the applications that they contain
  (.app's). Many users may not notice any difference, but two groups of
  Catalina users will be affected: those that use the "racket" binary
  directly, and those that download the ".tgz" bundles. In both cases,
  the operating system is likely to inform you that the given executable
  is not trusted, or that the developer can't be verified. Fortunately,
  both groups of users are probably also running commands at in a shell,
  and the solution for both groups is the same: you can disable the
  quarantine flag using the `xattr` command, e.g.

  xattr -d /path/to/racket

  TL;DR: Everything is fine. Read this note again if you run into problems.

The following people contributed to this release:

Alex Knauth, Alexander Shopov, Alexis King, Ayman Osman, Ben Greenman,
Bert De Ketelaere, Bogdan Popa, Caleb Allen, Chuan Wei Foo, David
Florness, Diego A. Mundo, Dominik Pantůček, Fred Fu, Geoffrey Knauth,
Gregory Cooper, Gustavo Massaccesi, James Bornholt, Jay McCarthy, Jens
Axel Søgaard, Jesse A. Tov, Jesse Alama, John Clements, Jon Zeppieri,
Leo Uino, Luke Nelson, Matthew Flatt, Matthias Felleisen, Max New, Mike
Sperber, Nick Thompson, Noah W M, Paulo Matos, Philip McGrath, Robby
Findler, Ryan Culpepper, Sam Tobin-Hochstadt, Shu-Hung You, Sorawee
Porncharoenwase, Stephen Chang, Thomas Dickerson, and William J. Bowman