# JAX v0.4.35 — JAX v0.4.35

- Product: JAX (https://whatsnew.fyi/product/jax)
- Vendor: Google
- Date: 2024-10-22
- Version: v0.4.35
- Original notes: https://github.com/jax-ml/jax/releases/tag/jax-v0.4.35
- Permalink: https://whatsnew.fyi/product/jax/releases/v0.4.35

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- **changed** — jax.numpy.isscalar now returns True for any array-like object with zero dimensions instead of only those with a weak dtype
- **removed** — jax.experimental.host_callback has been removed after deprecation since March 2024
- **added** — jax.lax.FftType introduced as a public name for the enum of FFT operations
- **deprecated** — jax.lib.xla_client.FftType has been deprecated
- **changed** — TPU: JAX now installs TPU support from the libtpu package rather than libtpu-nightly
- **deprecated** — jax.lib.xla_client.PaddingType has been deprecated
- **deprecated** — The default behavior of jax.pure_callback and jax.extend.ffi.ffi_call under vmap and the vectorized parameter have been deprecated in favor of vmap_method
- **deprecated** — jax.lib.xla_client.register_custom_call_target has been deprecated in favor of the JAX FFI
- **deprecated** — jax.lib.xla_client.dtype_to_etype, jax.lib.xla_client.ops, jax.lib.xla_client.shape_from_pyval, jax.lib.xla_client.PrimitiveType, jax.lib.xla_client.Shape, jax.lib.xla_client.XlaBuilder, and jax.lib.xla_client.XlaComputation have been deprecated in favor of StableHLO

* Breaking Changes
  * `jax.numpy.isscalar` now returns True for any array-like object with
    zero dimensions. Previously it only returned True for zero-dimensional
    array-like objects with a weak dtype.
  * `jax.experimental.host_callback` has been deprecated since March 2024, with
    JAX version 0.4.26. Now we removed it.
    See `#20385` for a discussion of alternatives.

* Changes:
  * `jax.lax.FftType` was introduced as a public name for the enum of FFT
    operations. The semi-public API `jax.lib.xla_client.FftType` has been
    deprecated.
  * TPU: JAX now installs TPU support from the `libtpu` package rather than
    `libtpu-nightly`. For the next few releases JAX will pin an empty version of
    `libtpu-nightly` as well as `libtpu` to ease the transition; that dependency
    will be removed in Q1 2025.

* Deprecations:
  * The semi-public API `jax.lib.xla_client.PaddingType` has been deprecated.
    No JAX APIs consume this type, so there is no replacement.
  * The default behavior of `jax.pure_callback` and
    `jax.extend.ffi.ffi_call` under `vmap` has been deprecated and so has
    the `vectorized` parameter to those functions. The `vmap_method` parameter
    should be used instead for better defined behavior. See the discussion in
    `#23881` for more details.
  * The semi-public API `jax.lib.xla_client.register_custom_call_target` has
    been deprecated. Use the JAX FFI instead.
  * The semi-public APIs `jax.lib.xla_client.dtype_to_etype`,
    `jax.lib.xla_client.ops`, 
    `jax.lib.xla_client.shape_from_pyval`, `jax.lib.xla_client.PrimitiveType`,
    `jax.lib.xla_client.Shape`, `jax.lib.xla_client.XlaBuilder`, and
    `jax.lib.xla_client.XlaComputation` have been deprecated. Use StableHLO
    instead.