# Racket v9.1 — Racket v9.1

- Product: Racket (https://whatsnew.fyi/product/racket)
- Vendor: Racket
- Date: 2026-02-24
- Version: v9.1
- Original notes: https://github.com/racket/racket/releases/tag/v9.1
- Permalink: https://whatsnew.fyi/product/racket/releases/v9.1

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **added** — Documentation organization and navigation can be specialized by language family
- **added** — The `for` form and its variants accept an `#:on-length-mismatch` specifier
- **added** — The `exn-classify-errno` function maps network and filesystem error numbers to posix-standard symbols
- **added** — The `make-struct-type` procedure can inherit the current inspector using a `'current` flag
- **added** — The `openssl/legacy` library provides access to OpenSSL's legacy provider for insecure and outdated algorithms
- **added** — The `system-type` function can report on platform and shared-object-library conventions with new flags
- **changed** — Behavior of Racket BC on certain character operations is changed to match Racket CS
- **changed** — DrRacket improves the GUI for choosing color schemes
- **changed** — DrRacket now displays curved syntax arrows with curvature indicating relative displacement
- **changed** — DrRacket's Insert Large Letters uses characters that match the comment syntax of the buffer's language
- **changed** — Typed Racket improves expected type propagation for keyword argument functions
- **changed** — Bundle configurations can better control conventions for locating shared object files with `--enable-sofind=<conv>` flags

----------------------------------------------------------------------

- Documentation organization and navigation can be specialized by
  language family, to allow users to interact with documentation in a
  way that is tailored to that language family. This is currently used
  by Rhombus.
- The `for` form and its variants accept an `#:on-length-mismatch`
  specifier. 3.18 Iterations and Comprehensions: for, for/list, ...
- DrRacket improves the GUI for choosing color schemes.
- DrRacket has curved syntax arrows. The degree of curvature indicates
  the relative left- or right-displacement of the arrow's target.
- DrRacket's "Insert Large Letters" uses characters that match the
  comment syntax of the buffer's language, making it useful (and fun!)
  in Rhombus.
- The `exn-classify-errno` maps network and filesystem error numbers
  on various platforms to posix-standard symbols, to enable more
  portable code. 10.2 Exceptions
- The behavior of Racket BC on certain character operations (most
  notably `eq?`)  is changed to match that of Racket CS, with a small
  performance penalty for these operations for BC programs. 19
  Performance 1.5 Implementations
- The `make-struct-type` procedure can inherit the current inspector
  using a `'current` flag. This is the default behavior, but there are
  situations in which it's not possible to refer to the current
  inspector. 5.2 Creating Structure Types
- Bundle configurations can better control the conventions for
  locating shared object files with the `--enable-sofind=<conv>`
  flags.
- The `system-type` function can report on platform and
  shared-object-library conventions with new flags. 15.8 Environment
  and Runtime Information
- The `openssl/legacy` library makes it possible to access OpenSSL's
  built-in "legacy" provider, to get access to insecure and outdated
  algorithms. OpenSSL: Secure Communication
- Typed Racket improves expected type propagation for keyword argument
  functions.
- There are many other repairs and documentation improvements!

The following people contributed to this release:

Alexander Shopov, beast-hacker, Bob Burger, Brad Lucier, Cadence
Ember, David Van Horn, evan, François-René Rideau, Gustavo
Massaccesi, Jacqueline Firth, Jade Sailor, Jason Hemann, Jens Axel
Søgaard, John Clements, Jonas Rinke, Matthew Flatt, Matthias
Felleisen, Mike Sperber, Noah Ma, Pavel Panchekha, Rob Durst, Robby
Findler, Ryan Culpepper, Sam Tobin-Hochstadt, Stephen De Gabrielle,
and Wing Hei Chan.

----------------------------------------------------------------------