# Polars 1.39.1 — Python Polars 1.39.1

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2026-03-17
- Version: 1.39.1
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.39.1
- Permalink: https://whatsnew.fyi/product/polars/releases/1.39.1

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** — Handle empty rolling windows in streaming engine

##### 🐞 Bug fixes

- Handle empty rolling windows in streaming engine (#26903)

##### 📖 Documentation

- Add documentation for on\_columns for LazyFrame pivot (#26859)

##### 🛠️ Other improvements

- Bump build deps used in ARM64 Windows release pipeline (#26892)

Thank you to all our contributors for making this release possible!
@Kevin-Patyk, @RenzoMXD, @TNieuwdorp, @dsprenkels, @gautamvarmadatla, @nameexhaustion, @nicholaslegrand102 and @ritchie46