●Change8

Migrating to Polars rs-0.51.0

Version rs-0.51.0 introduces 1 breaking change. This guide details how to update your code.

Released: 9/16/2025

1
Breaking Changes
1
Migration Steps
17
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

pl.Exprpl.Series.shiftpl.DataFrame.map_columnspl.Expr.logpl.Expr.diffpl.Series.__arrow_c_stream__pl.dt.epochpl.Expr.rechunkpl.read_excelpl.LazyGroupBypl.concat_listpl.rolling_meanpl.merge_sortedpl.row_encodepl.Datepl.meanpl.cast

Breaking Changes

●Issue #1

Removed, deprecated, or changed eager Expressions (Exprs) to be lazy compatible. Users relying on eager evaluation of expressions that are now lazy may see changes in execution behavior or errors if they expected immediate results.

Migration Steps

  1. 1
    Review code that relied on eager evaluation of Expressions (Exprs) and ensure compatibility with the new lazy evaluation model, especially if immediate results were expected.

Release Summary

This release introduces significant performance improvements across the streaming engine, new features like array support for unique counts and AWS role assumption guides, and addresses numerous bugs, notably around serialization and type handling. The most critical change is the transition of some eager Expressions to be lazy compatible.

Need More Details?

View the full release notes and all changes for Polars rs-0.51.0.

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