# PyWavelets 1.4.0 Release Notes

We are very pleased to announce the release of PyWavelets 1.4. This release is a minor update to 1.3.0. It adds wheels for Python 3.11 and drops support for Python 3.7.

There is one new utility function, pywt.frequency2scale, that can be used to determine CWT scale factors corresponding to a given (normalized) frequency. It is the inverse of the existing pywt.scale2frequency.

A detailed change log is provided below.

## Authors

- Christian Clauss +

- Gregory R. Lee

- Orion Poplawski +

- Trevor Clark +

## Reviewers

- Gregory R. Lee

- Ralf Gommers

A total of 5 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

### Issues closed for v1.4

- #640: test_accuracy_precomputed_cwt fails on aarch64

### Pull requests for v1.4

- #629: Fix twine-based uploads to PyPI

- #635: added a frequency2scale function as the dual to scale2frequency

- #641: test_cwt_batch can have small differences on some arches (resolves #640)

- #647: provide setuptools upper bound for robustness against future changes

- #648: Run GitHub actions test cases using Python 3.11

- #649: Update wheel building workflow to include Python 3.11

- #650: Upgrade GitHub Actions

- #651: Fix typos discovered by codespell

- #654: Remove string_types, which is a remnant of Python 2 support