[export] Set the default export serialization version to 8.

This version has been supported by XlaCallModule since July 21, 2023 and we are now past the forward-compatibility window.

See https://github.com/google/jax/blob/main/jax/experimental/jax2tf/README.md#native-serialization-versions

PiperOrigin-RevId: 568777006

jax/_src/config.py

@@ -691,8 +691,8 @@ def update_thread_local_jit_state(**kw):
     # Note: bump the default serialization version at least one month after
     # we update XlaCallModule to support the new version, so that serialized
     # modules are forward compatible with deployed versions of XlaCallModule.
-    # Version 7 of XlaCallModule is supported since July 12th, 2023.
-    default=int_env('JAX_SERIALIZATION_VERSION', 7),
+    # Version 8 of XlaCallModule is supported since July 21th, 2023.
+    default=int_env('JAX_SERIALIZATION_VERSION', 8),
     help=(
         'The version number to use for native serialization. This must be '
         'within the range of versions supported by the tf.XlaCallModule '

jax/experimental/jax2tf/README.md

@@ -820,12 +820,14 @@ We list here a history of the serialization version numbers:
   * Version 7 adds support for `stablehlo.shape_assertion` operations and
     for `shape_assertions` specified in `disabled_checks`.
     See [Errors in presence of shape polymorphism](https://github.com/google/jax/blob/main/jax/experimental/jax2tf/README.md#errors-in-presence-of-shape-polymorphism). Supported by XlaCallModule
-    since July 12th, 2023 (cl/547482522) and
-    available in JAX serialization since July 20th, 2023 (JAX 0.4.14).
+    since July 12th, 2023 (cl/547482522),
+    available in JAX serialization since July 20th, 2023 (JAX 0.4.14),
+    and the default since August 12th, 2023 (JAX 0.4.15).
   * Version 8 adds support for the `jax.uses_shape_polymorphism` module
     attribute and enables the shape refinement pass only when the
     attribute is present. Supported by XlaCallModule since July 21st, 2023
-    (cl/549973693) and available in JAX since July 26th, 2023 (JAX 0.4.14).
+    (cl/549973693), available in JAX since July 26th, 2023 (JAX 0.4.14),
+    and the default since September 27th, 2023 (JAX 0.4.17).
 
 
 ## Known issues