# JAX v0.8.0 — JAX v0.8.0

- Product: JAX (https://whatsnew.fyi/product/jax)
- Vendor: Google
- Date: 2025-10-15
- Version: v0.8.0
- Original notes: https://github.com/jax-ml/jax/releases/tag/jax-v0.8.0
- Permalink: https://whatsnew.fyi/product/jax/releases/v0.8.0

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Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **changed** — JAX is changing the default jax.pmap implementation to one implemented in terms of jax.jit and jax.shard_map
- **removed** — The auto= parameter of jax.experimental.shard_map.shard_map has been removed
- **removed** — JAX no longer allows passing objects that support __jax_array__ directly to jit-ed functions
- **changed** — jax.numpy.cov now returns NaN for empty arrays and matches NumPy 2.2 behavior for single-row design matrices
- **removed** — JAX no longer accepts Array values where a dtype value is expected
- **removed** — The deprecated function jax.interpreters.mlir.custom_call was removed
- **removed** — The jax.util, jax.extend.ffi, and jax.experimental.host_callback modules have been removed
- **removed** — The deprecated symbol jax.custom_derivatives.custom_jvp_call_jaxpr_p was removed
- **changed** — jax.experimental.multihost_utils.process_allgather raises an error when the input is a jax.Array and not fully-addressable and tiled=False
- **removed** — From jax.experimental.compilation_cache, the deprecated symbols is_initialized and initialize_cache were removed
- **removed** — The deprecated function jax.interpreters.xla.canonicalize_dtype was removed
- **removed** — jaxlib.hlo_helpers has been removed
- **removed** — The option jax_cpu_enable_gloo_collectives has been removed
- **removed** — The previously-deprecated interpolation argument to jax.numpy.percentile and jax.numpy.quantile has been removed
- **removed** — The JAX-internal for_loop primitive was removed
- **changed** — jax.numpy.trimzeros now errors for non-1D input
- **changed** — The where argument to jax.numpy.sum and other reductions is now required to be boolean
- **removed** — The deprecated functions in jax.dlpack, jax.errors, jax.lib.xla_bridge, jax.lib.xla_client, and jax.lib.xla_extension were removed
- **removed** — jax.interpreters.mlir.dense_bool_array was removed
- **changed** — jax.numpy.linalg.eig now returns a namedtuple with attributes eigenvalues and eigenvectors instead of a plain tuple
- **changed** — jax.grad and jax.vjp will now round primals to float32 if float64 mode is not enabled

* Breaking changes:

  * JAX is changing the default `jax.pmap` implementation to one implemented in
    terms of `jax.jit` and `jax.shard_map`. `jax.pmap` is in maintenance mode
    and we encourage all new code to use `jax.shard_map` directly. See the
    [migration guide](https://docs.jax.dev/en/latest/migrate_pmap.html) for
    more information.
  * The `auto=` parameter of `jax.experimental.shard_map.shard_map` has been
    removed. This means that `jax.experimental.shard_map.shard_map` no longer
    supports nesting. If you want to nest shard_map calls, please use
    `jax.shard_map`.
  * JAX no longer allows passing objects that support `__jax_array__` directly
    to, e.g. `jit`-ed functions. Call `jax.numpy.asarray` on them first.
  * `jax.numpy.cov` is now returns NaN for empty arrays ({jax-issue}`#32305`),
    and matches NumPy 2.2 behavior for single-row design matrices ({jax-issue}`#32308`).
  * JAX no longer accepts `Array` values where a `dtype` value is expected. Call
    `.dtype` on these values first.
  * The deprecated function `jax.interpreters.mlir.custom_call` was
    removed.
  * The `jax.util`, `jax.extend.ffi`, and `jax.experimental.host_callback`
    modules have been removed. All public APIs within these modules were
    deprecated and removed in v0.7.0 or earlier.
  * The deprecated symbol `jax.custom_derivatives.custom_jvp_call_jaxpr_p`
    was removed.
  * `jax.experimental.multihost_utils.process_allgather` raises an error when
    the input is a jax.Array and not fully-addressable and `tiled=False`. To fix
    this, pass `tiled=True` to your `process_allgather` invocation.
  * from `jax.experimental.compilation_cache`, the deprecated symbols
    `is_initialized` and `initialize_cache` were removed.
  * The deprecated function `jax.interpreters.xla.canonicalize_dtype`
    was removed.
  * `jaxlib.hlo_helpers` has been removed. Use `jax.ffi` instead.
  * The option `jax_cpu_enable_gloo_collectives` has been removed. Use
    `jax_cpu_collectives_implementation` instead.
  * The previously-deprecated `interpolation` argument to
    `jax.numpy.percentile` and `jax.numpy.quantile` has been
    removed; use `method` instead.
  * The JAX-internal `for_loop` primitive was removed. Its functionality,
    reading from and writing to refs in the loop body, is now directly
    supported by `jax.lax.fori_loop`. If you need help updating your
    code, please file a bug.
  * `jax.numpy.trimzeros` now errors for non-1D input.
  * The `where` argument to `jax.numpy.sum` and other reductions is now
    required to be boolean. Non-boolean values have resulted in a
    `DeprecationWarning` since JAX v0.5.0.
  * The deprecated functions in  `jax.dlpack`,  `jax.errors`, 
    `jax.lib.xla_bridge`,  `jax.lib.xla_client`, and 
    `jax.lib.xla_extension` were removed.
  * `jax.interpreters.mlir.dense_bool_array` was removed. Use MLIR APIs to
    construct attributes instead.

* Changes
  * `jax.numpy.linalg.eig` now returns a namedtuple (with attributes
    `eigenvalues` and `eigenvectors`) instead of a plain tuple.
  * `jax.grad` and `jax.vjp` will now round always primals to
    `float32` if `float64` mode is not enabled.
  * `jax.dlpack.from_dlpack` now accepts arrays with non-default layouts,
    for example, transposed.
  * The default nonsymmetric eigendecomposition on NVIDIA GPUs now uses
    cusolver. The magma and LAPACK implementations are still available via the
    new `implementation` argument to `jax.lax.linalg.eig`
    ({jax-issue}`#27265`). The `use_magma` argument is now deprecated in favor
    of `implementation`.
  * `jax.numpy.trim_zeros` now follows NumPy 2.2 in supporting
    multi-dimensional inputs.

* Deprecations
  * `jax.experimental.enable_x64` and `jax.experimental.disable_x64`
    are deprecated in favor of the new non-experimental context manager
    `jax.enable_x64`.
  * `jax.experimental.shard_map.shard_map` is depreca

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