# Crystal 1.20.1

- Product: Crystal (https://whatsnew.fyi/product/crystal)
- Vendor: Crystal Language
- Date: 2026-04-29
- Version: 1.20.1
- Original notes: https://github.com/crystal-lang/crystal/releases/tag/1.20.1
- Permalink: https://whatsnew.fyi/product/crystal/releases/1.20.1

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'.

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- **fixed** — Fix issues in OpenSSL Kernel TLS
- **changed** — OpenSSL Kernel TLS support should be opt-in
- **added** — Add HTTP::Headers#to_json and #to_yaml
- **fixed** — Range#sample eventually loses randomness
- **fixed** — Don't parse debug sections from bare threads
- **fixed** — Fix lexing macro delimiter state inside literals
- **fixed** — Revert "Refactor Formatter code for simplification"

###### Bugfixes

###### stdlib

- _(crypto)_ Fix issues in OpenSSL Kernel TLS ([#16888], thanks @ysbaddaden)
- _(crypto)_ OpenSSL Kernel TLS support should be opt-in ([#16897], thanks @ysbaddaden)
- _(networking)_ **[regression]** Add `HTTP::Headers#to_json` and `#to_yaml` ([#16890], thanks @straight-shoota)
- _(runtime)_ **[regression]** `Range#sample` eventually loses randomness ([#16853], thanks @ysbaddaden)
- _(runtime)_ don't parse debug sections from bare threads ([#16877], thanks @ysbaddaden)

[#16853]: https://github.com/crystal-lang/crystal/pull/16853
[#16877]: https://github.com/crystal-lang/crystal/pull/16877
[#16888]: https://github.com/crystal-lang/crystal/pull/16888
[#16890]: https://github.com/crystal-lang/crystal/pull/16890
[#16897]: https://github.com/crystal-lang/crystal/pull/16897

###### compiler

- _(parser)_ **[regression]** Fix lexing macro delimiter state inside literals ([#16892], thanks @straight-shoota)

[#16892]: https://github.com/crystal-lang/crystal/pull/16892

###### tools

- _(formatter)_ **[regression]** Revert "Refactor `Formatter` code for simplification" ([#16885], thanks @straight-shoota)

[#16885]: https://github.com/crystal-lang/crystal/pull/16885

###### Refactor

###### stdlib

- _(runtime)_ Refactor `Exception::CallStack` for better boundaries ([#16896], thanks @straight-shoota)

[#16896]: https://github.com/crystal-lang/crystal/pull/16896

###### Infrastructure

- Changelog for 1.20.1 ([#16898], thanks @straight-shoota)

[#16898]: https://github.com/crystal-lang/crystal/pull/16898