* Preview for the new functional API (see [notebook](https://github.com/py-why/dowhy/blob/main/docs/source/example_notebooks/dowhy_functional_api.ipynb)). The new API (in experimental stage) allows for a modular use of the different functionalities and includes separate fit and estimate methods for causal estimators. Please leave your feedback [here](https://github.com/py-why/dowhy/discussions/779). The old DoWhy API based on CausalModel should work as before. (andresmor-ms)
* Faster, better sensitivity analyses.
* Many refutations now support joblib for parallel processing and show a progress bar (astoeffelbauer, yemaedahrav).
* Non-linear sensitivity analysis [ [`Chernozhukov, Cinelli, Newey, Sharma & Syrgkanis (2021)](https://arxiv.org/abs/2112.13398), [example notebook](https://github.com/py-why/dowhy/blob/main/docs/source/example_notebooks/sensitivity_analysis_nonparametric_estimators.ipynb) ] (anusha0409)
* E-value sensitivity analysis [ [Ding & Vanderweele (2016)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4820664/), [example notebook](https://github.com/py-why/dowhy/blob/main/docs/source/example_notebooks/sensitivity_analysis_testing.ipynb)] (jlgleason)
* New API for [unit change attribution](https://www.pywhy.org/dowhy/v0.9/dowhy.gcm.html#dowhy.gcm.unit_change.unit_change) (kailashbuki)
* New quality option [`BEST` for auto-assignment](https://www.pywhy.org/dowhy/v0.9/dowhy.gcm.html#module-dowhy.gcm.auto) of causal mechanisms, which uses the optional auto-ML library [AutoGluon](https://auto.gluon.ai/) (bloebp)
* Better conditional independence tests through the [causal-learn](https://github.com/cmu-phil/causal-learn) package (bloebp)
* Algorithms for computing efficient backdoor sets [ [example notebook](https://github.com/py-why/dowhy/blob/main/docs/source/example_notebooks/dowhy_efficient_backdoor_example.ipynb) ] (esmucler)
* Support for estimating controlled direct effect (amit-sharma)
* Support for multi-valued treatments for econml estimators (EgorKraevTransferwise)
* New PyData theme for [documentation](https://www.pywhy.org/dowhy/) with new homepage, Getting started guide, revised User Guide and examples page (petergtz)
* A [contributing guide](https://github.com/py-why/dowhy/blob/main/docs/source/contributing/contributing-code.rst) and simplified instructions for new contributors (MichaelMarien)
* Streamlined dev environment using Poetry for managing dependencies and project builds (darthtrevino)
* Bug fixes