diff --git a/CHANGELOG.md b/CHANGELOG.md
index 42d705f34..f70261789 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,11 @@ PLEASE REMEMBER TO CHANGE THE '..main' WITH AN ACTUAL TAG in GITHUB LINK.
     unhashable static arguments into the function object.
   * `jax.util.partial` was an accidental export that has now been removed. Use
     `functools.partial` from the Python standard library instead.
+* New features:
+  * A C++ code-path improving the dispatch time for pmap is now the default when
+    using jaxlib 0.1.72 or newer. The feature can be disabled using the
+    `--experimental_cpp_pmap` flag (or `JAX_CPP_PMAP` environment variable).
+    It improves dispatch time,
 
 ## jax 0.2.21 (Sept 23, 2021)
 * [GitHub
diff --git a/jax/_src/api.py b/jax/_src/api.py
index a2cb841cb..8be9e02ad 100644
--- a/jax/_src/api.py
+++ b/jax/_src/api.py
@@ -104,12 +104,13 @@ FLAGS = flags.FLAGS
 
 flags.DEFINE_bool(
     "experimental_cpp_jit", bool_env("JAX_CPP_JIT", True),
-    "A temporary flag enabling the C++ jax.jit fast path."
+    "A flag enabling the C++ jax.jit fast path."
     "Set this to `False` only if it crashes otherwise and report "
     "the error to the jax-team.")
 flags.DEFINE_bool(
-    "experimental_cpp_pmap", bool_env("JAX_CPP_PMAP", False),
-    "A temporary flag enabling the C++ jax.pmap fast path. Until the default "
+    "experimental_cpp_pmap",
+    bool_env("JAX_CPP_PMAP", jax._src.lib._xla_extension_version >= 39),
+    "A flag enabling the C++ jax.pmap fast path. Until the default "
     "is switched to True, the feature is not supported and possibly broken "
     "(e.g. it may use unreleased code from jaxlib.")