Polars py-1.42.1 was published on June 30, 2026, with a practical patch set for parquet scans, query correctness, and runtime failure cases. The most useful change for data engineers is sampled resolve mode for multi file parquet metadata, which targets one of the dull but expensive parts of reading many files.

Polars py-1.42.0 was published on June 24, 2026, with cloud IO controls, Parquet and Delta file pruning, and targeted fixes for SQL, streaming, and sink workloads. For data engineering teams using Polars in batch or lakehouse jobs, the most important change is less wasted scan work through bytes based cloud concurrency, row group skipping, and better metadata resolution. This is a regular release, not a prerelease.