# date-fns v4.3.0

- Product: date-fns (https://whatsnew.fyi/product/date-fns)
- Vendor: date-fns
- Date: 2026-05-22
- Version: v4.3.0
- Original notes: https://github.com/date-fns/date-fns/releases/tag/v4.3.0
- Permalink: https://whatsnew.fyi/product/date-fns/releases/v4.3.0

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'.

---

- **fixed** — Fixed missing modularized optimization fallback for Next.js and others
- **fixed** — Fixed pt locale first day of week to be Sunday
- **fixed** — Fixed zh-CN, zh-HK, and zh-TW locale month parsing for October, November, and December

Kudos to [@ImRodry](https://github.com/ImRodry) and [@puneetdixit200](https://github.com/puneetdixit200) for their contributions.

###### Fixed

- Fixed missing modularized optimization fallback ([for Next.js and others](https://x.com/kossnocorp/status/1731181274579325260)). See [#4193](https://x.com/kossnocorp/status/1731181274579325260).

- Fixed `pt` locale first day of week to be Sunday. See [#4195](https://github.com/date-fns/date-fns/pull/4195) by [@ImRodry](https://github.com/ImRodry).

- Fixed `zh-CN`, `zh-HK`, and `zh-TW` locale month parsing for October, November, and December. See [#4194](https://github.com/date-fns/date-fns/pull/4194) by [@puneetdixit200](https://github.com/puneetdixit200).