Racket v9.1 is now available, introducing language-specific documentation navigation first implemented for Rhombus. The `for` iteration forms gain a new `#:on-length-mismatch` specifier for better list handling. DrRacket receives visual upgrades including curved syntax arrows and improved color scheme selection.

These updates refine Racket's language-oriented programming model, making it easier to work with specialized dialects like Rhombus. The `exn-classify-errno` function improves cross-platform error handling, while changes to Racket BC's character operations unify behavior with Racket CS at a minor performance cost.

Developers should note the new `openssl/legacy` library, which provides access to outdated cryptographic algorithms. The release also enhances `make-struct-type` inheritance and bundle configuration controls. Users must run `raco pkg migrate 9.0` to update packages properly.