What is the expected enhancement?

We need to update PyO3 to the latest version. Currently we still need to wait for rust-numpy to also be updated.

There is a migration guide available at https://pyo3.rs/v0.21.0/migration.html. This migration will be more involved due to the future removal of GIL refs. We can enable the feature gil-refs to make the process smoother, but inevitably it will be removed in a future upgrade