diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2cb23c..7b5e17a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # waveform-data.js
 
+## v4.0.0 (2021/04/24)
+
+ * Added disable_worker option to WaveformData.createFromAudio()
+   (@Christilut, @chrisn)
+ * Added WaveformData.toJSON() method (@chrisn)
+ * Updated TypeScript declarations (@Kangaroux, @chrisn)
+ * Added d3.js example, see demo/d3.html (@chrisn)
+ * Reworded error messages (@chrisn)
+ * The WaveformData.resample() method no longer accepts a single number
+   (@chrisn)
+
 ## v3.3.4 (2020/09/07)
 
  * Improve browser compatibility (@Dantist)
diff --git a/package-lock.json b/package-lock.json
index 1ca8f21..bbfe785 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "waveform-data",
-  "version": "3.3.4",
+  "version": "4.0.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -5929,12 +5929,6 @@
         }
       }
     },
-    "y18n": {
-      "version": "5.0.5",
-      "resolved": "https://registry.npmjs.org/y18n/-/y18n-5.0.5.tgz",
-      "integrity": "sha512-hsRUr4FFrvhhRH12wOdfs38Gy7k2FFzB9qgN9v3aLykRq0dRcdcpz5C9FxdS2NuhOrI/628b/KSTJ3rwHysYSg==",
-      "dev": true
-    },
     "yallist": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-2.1.2.tgz",
diff --git a/package.json b/package.json
index 8f4ffc9..61d7ceb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "waveform-data",
-  "version": "3.3.4",
+  "version": "4.0.0",
   "description": "Audio Waveform Data Manipulation API – resample, offset and segment waveform data in JavaScript",
   "main": "waveform-data.js",
   "types": "waveform-data.d.ts",