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 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 deprecated; going forward use jax.shard_map.
• jax.experimental.pjit.pjit is deprecated; going forward use jax.jit.