diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98530327..91516c79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,15 +1,18 @@
 # CHANGELOG
 
-## 0.9.0 - UNRELEASED
+## 0.9.0 - 2022-03-25
 
 Requires Panda system version >= 4.2.1
 
- * **BREAKING** Add `O_ddP_O` base acceleration to robot state
- * **BREAKING** New `base_acceleration_initialization_timeout` & `base_acceleration_invalid_reading` reflexes 
+ * **BREAKING** Add `O_ddP_O` base acceleration to robot state, harcoded to `{0, 0, -9.81}`.
+ * **BREAKING** New `base_acceleration_initialization_timeout`, `base_acceleration_invalid_reading`
+                `cartesian_spline_motion_generator_violation` and 
+                `joint_via_motion_generator_planning_joint_limit_violation` reflexes.
  * Adjust network error messages. Distinguish between problems resulting from:
     - a wrong network configuration. A message is shown after a timeout of 60 seconds.
     - a missing FCI feature or a blocked port due to Single Point of Control. An immediate error
       response is shown.
+ * Changed signature of `franka::Model::gravity` to use `O_ddP_O` in the robot state.
 
 ## 0.8.0 - 2020-04-29
 
diff --git a/include/franka/robot_state.h b/include/franka/robot_state.h
index 452bb569..9f92773c 100644
--- a/include/franka/robot_state.h
+++ b/include/franka/robot_state.h
@@ -331,6 +331,7 @@ struct RobotState {
    * Linear component of the acceleration of the robot's base, expressed in frame parallel to the
    * @ref o-frame "base frame", i.e. the base's translational acceleration. If the base is resting
    * this shows the direction of the gravity vector.
+   * It is harcoded for now to `{0, 0, -9.81}`.
    */
   std::array<double, 3> O_ddP_O{};  // NOLINT(readability-identifier-naming)