Polars releases an upgrade guide alongside each breaking release. This guide is intended to help you upgrade from an older Polars version to the new version.
Each guide contains all breaking changes that were not previously deprecated, as well as any significant new deprecations.
A full list of all changes is available in the changelog.
There are no upgrade guides yet for Rust releases. These will be added once the rate of breaking changes to the Rust API slows down and a deprecation policy is added.