# Polars 1.44.0 — Python Polars 1.44.0

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2026-08-24
- Version: 1.44.0
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.44.0
- Permalink: https://whatsnew.fyi/product/polars/releases/1.44.0

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'.

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- **deprecated** — Deprecate rechunk parameter for all read/scan functions
- **deprecated** — Deprecate Expr.rechunk()
- **deprecated** — Deprecate struct.rename_fields() with an incorrect number of fields
- **changed** — Relax default CloudRetryConfig for rate limit stability
- **changed** — Improve performance of when/then/otherwise by masking out unevaluated elements
- **added** — Support integer fixed-array dot products
- **added** — SQL correlated in
- **added** — Support more join_types in join_where
- **added** — Support Iceberg schema evolution
- **added** — Support Iceberg table with V3 deletion vectors in native scan_iceberg
- **added** — Support Iceberg snapshot properties
- **added** — Expose sinked_paths_callback on sink_parquet as unstable parameter
- **added** — Add infer_schema_files to CSV inference hint
- **added** — Add native fixed-array dot
- **added** — Support Iceberg object storage paths
- **added** — Add adaptive HTTP rate-limiter for cloud IO
- **added** — Add struct.drop()
- **fixed** — Fix assertion error or incorrect data load from parquet written by fastparquet
- **fixed** — Fix OOC spilling of categoricals
- **fixed** — Raise on overflow in Decimal sum instead of silently wrapping

##### ⚠️ Deprecations

- Deprecate `rechunk` parameter for all read/scan functions (#28063)
- Deprecate `Expr.rechunk()` (#28692)
- Deprecate `struct.rename_fields()` with an incorrect number of fields (#28672)

##### 🚀 Performance improvements

- Add private env var toggle for HTTP rate limit (#28882)
- Relax default `CloudRetryConfig` for rate limit stability (#28885)
- Elide generic cross join on subquery decorrelation in equality predicates (#28876)
- cache CTE's in SQL layer (#28864)
- Allow CSPE if manual caches are set (#28859)
- Lower unqualified join predicates to inner joins in SQL (#28854)
- Rechunk `mask` for DataFrame `filter` (#28762)
- Improve performance of when/then/otherwise by masking out unevaluated elements (#28498)
- Drop unused projections in filter on streaming engine (#28713)
- Retain Parquet `Partial` metadata on filter (#28737)

##### ✨ Enhancements

- Support integer fixed-array dot products (#28829)
- SQL correlated in (#28927)
- Support more join\_types in `join_where` (#28880)
- Support Iceberg schema evolution (#28794)
- SQL conformance (#28494)
- Introduce `RemoteEngine` and a common base class for all engines (#28800)
- Support Iceberg table with V3 deletion vectors in native `scan_iceberg` (#28772)
- Support Iceberg snapshot properties (#28793)
- Expose `sinked_paths_callback` on `sink_parquet` as unstable parameter (#28814)
- Add `infer_schema_files` to CSV inference hint (#28809)
- Add native fixed-array dot (#28504)
- Export query metrics to polars\_cloud (#28757)
- Support Iceberg object storage paths (#28634)
- More CSEE simplification (#28731)
- Improve error in Series constructor with name in context (#28743)
- Add adaptive HTTP rate-limiter for cloud IO (#28591)
- Add `struct.drop()` (#28666)
- Improve error message when CSV name de-duplication fails (#28658)
- Always keep first metadata per source for Parquet (#28661)
- Improve plan-time row estimates for multi-file parquet scans (#28380)
- Expose array and plugin function views in Python visitor (#28635)

##### 🐞 Bug fixes

- SQL handle quantified comparisons against a subquery (#28929)
- Fix SQL subquery qualified lowering and cache row-index (#28926)
- Clippy-stable failures (#28919)
- Use uuidv7 for cloud observed queries (#28910)
- Unsoundness in AnyValue::into\_static for structs (#28889)
- Invalidate suborders on projection (#28866)
- Ensure SQL function registry is available in isolated subqueries (#28881)
- Handle null in Expr.is\_not\_nan (#28883)
- Ensure eager `unpivot` column selection aligns with the lazy engine (#28846)
- Fix assertion error / incorrect data load from  parquet written by fastparquet (#28656)
- Fix projection pushdown incorrect `select()` height (#28751)
- Restore `monitoring` as an engine-level parameter (#28821)
- Bincode serialization of IR hints (#28837)
- Retain datetime inference across CSV fallback (#28663)
- Avoid chunk fragmentation on bool agg `min` and `max` (#28789)
- Merge join with coalesce and empty suffix (#28799)
- Wrong function name call in test (#28801)
- Preserve row mapping in nested over expressions (#28767)
- Restore CI compatibility with NumPy 2.5.2 (#28782)
- Do not deduplicate inherently nondeterministic plan nodes (#28768)
- Fix OOC spilling of categoricals (#28761)
- Correct partitionable filter handling for pivot (#28749)
- Small typo in docstring (#28763)
- Avoid chunk fragmentation on bool agg `any` and `all` (#28754)
- Ignore nans in (min|max)\_horizontal (#28710)
- Correct function display for str.replace\_all (#28742)
- Exclude debug tests from nodebug streaming run (#28747)
- Convert predicate series dtype during prefiltered parquet reading (#28711)
- Do not remove nested caches when performing predicate pushdown past a cache node (#28740)
- Correct handling of nulls at the start of business day functions (#28703)
- Do not panic when exceeding Parquet metadata scan cache (#28721)
- Remove cr

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