diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c70b5a..c930601 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.9.0](https://github.com/metonym/svelte-intersection-observer/releases/tag/v0.9.0) - 2021-10-05
+
+- improve TypeScript definitions for dispatched events
+  - `on:observe`: `event.detail.isIntersecting` is a `boolean`
+  - `on:intersect`: `event.detail.isIntersecting` can only be `true`
+
 ## [0.8.0](https://github.com/metonym/svelte-intersection-observer/releases/tag/v0.8.0) - 2021-09-02
 
 - use `.svelte.d.ts` extension for component TypeScript definition
diff --git a/package.json b/package.json
index b689e45..18b2a0d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte-intersection-observer",
-  "version": "0.8.0",
+  "version": "0.9.0",
   "license": "MIT",
   "description": "Detect if an element is in the viewport using the Intersection Observer API",
   "author": "Eric Liu (https://github.com/metonym)",