diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -25,3 +25,36 @@
 
 What's New in Libc++ 9.0.0?
 ===========================
+
+Fixes
+-----
+
+* Minor fixes to `std::chrono` operators.
+* libc++ now correctly handles Objective-C++ ARC qualifiers in `std::is_pointer`.
+* `std::span` general updates and fixes.
+* Updates to the `std::abs` implementation.
+* `std::to_chars` now adds leading zeros.
+* Ensure `std::tuple` is trivially constructible.
+* `std::aligned_union` now works in C++03.
+* Output of nullptr to `std::basic_ostream` is formatted properly.
+
+Features
+--------
+
+* Implemented P0608: sane variant converting constructor.
+* Added `ssize` function.
+* Added `front` and `back` methods in `std::span`.
+* `std::is_unbounded_array` and `std::is_bounded_array` added to type traits.
+* `std::atomic` now includes many new features and specialization including improved Freestanding support.
+* Added `std::midpoint` and `std::lerp` math functions.
+* Added the function `std::is_constant_evaluated`.
+* Erase-like algorithms now return size type.
+* Added `contains` method to container types.
+* `std::swap` is now a constant expression.
+
+Updates
+-------
+
+* libc++ dropped support for GCC 4.9; we now support GCC 5.1 and above.
+* libc++ added explicit support for WebAssembly System Interface (WASI).
+* Progress towards full support of rvalues and variadics in C++03 mode. `std::move` and `std::forward` now both work in C++03 mode.
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