Version 1.5

Legend for changelogs

  • Major Feature something big that you couldn’t do before.

  • Feature something that you couldn’t do before.

  • Efficiency an existing feature now may not require as much computation or memory.

  • Enhancement a miscellaneous minor improvement.

  • Fix something that previously didn’t work as documented – or according to reasonable expectations – should now work.

  • API Change you will need to change your code to have the same effect in the future; or a feature will be removed in the future.

Version 1.5.0

In Development

Support for building with Meson

Meson is now supported as a build backend, see Building with Meson for more details.

#28040 by Loïc Estève

TODO Fill more details before the 1.5 release, when the Meson story has settled down.

Metadata Routing

The following models now support metadata routing in one or more or their methods. Refer to the Metadata Routing User Guide for more details.











  • Enhancement CV splitters that ignores the group parameter now raises a warning when groups are passed in to split. #28210 by


  • Feature pipeline.FeatureUnion can now use the verbose_feature_names_out attribute. If True, get_feature_names_out will prefix all feature names with the name of the transformer that generated that feature. If False, get_feature_names_out will not prefix any feature names and will error if feature names are not unique. #25991 by Jiawei Zhang.

Code and documentation contributors

Thanks to everyone who has contributed to the maintenance and improvement of the project since version 1.4, including:

TODO: update at the time of the release.