diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9253890..e4057cad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,71 @@
 
 All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
 
+## [4.0.0](https://www.github.com/lholmquist/sdk-javascript/compare/v3.1.0...v4.0.0) (2020-08-26)
+
+
+### ⚠ BREAKING CHANGES
+
+* This validates the value of the cloud event extension based on the spec, 
+* This changes the modules name from cloudevents-sdk to cloudevents
+* **src:** * Extension names are now validated during object creation.  The values are defined by the specification, and can be lowercase(a-z) or digits(0-9) and must be no longer that 20 characters
+* **src:** * This change makes the CloudEvent Read-only and validates the input during object creation.
+* change CloudEvent to use direct object notation and get/set properties (#172)
+* refactor HTTP bindings and specifications (#165)
+* expose a version agnostic event emitter (#141)
+* **unmarshaller:** remove asynchronous 0.3 unmarshaller API (#126)
+
+### Features
+
+* add types to package.json ([#216](https://www.github.com/lholmquist/sdk-javascript/issues/216)) ([4265281](https://www.github.com/lholmquist/sdk-javascript/commit/42652819f32df245e4e314d2df3758f6e5ca6926))
+* add ValidationError type extending TypeError ([#151](https://www.github.com/lholmquist/sdk-javascript/issues/151)) ([09b0c76](https://www.github.com/lholmquist/sdk-javascript/commit/09b0c76826657222f6dc93fa377349a62e9b628f))
+* expose a mode and version agnostic event receiver ([#120](https://www.github.com/lholmquist/sdk-javascript/issues/120)) ([54f242b](https://www.github.com/lholmquist/sdk-javascript/commit/54f242b79e03dbba382f5016a1279ddf392c354f))
+* expose a version agnostic event emitter ([#141](https://www.github.com/lholmquist/sdk-javascript/issues/141)) ([250a0a1](https://www.github.com/lholmquist/sdk-javascript/commit/250a0a144c5fbeac237e04dcd3f54e05dc30fc70))
+* formatter.js es6 ([#87](https://www.github.com/lholmquist/sdk-javascript/issues/87)) ([c36f194](https://www.github.com/lholmquist/sdk-javascript/commit/c36f1949d0176574ace24fee87ce850f01f1e2f5))
+* introduce browser support ([#201](https://www.github.com/lholmquist/sdk-javascript/issues/201)) ([8b2725b](https://www.github.com/lholmquist/sdk-javascript/commit/8b2725b10a10ba5da842e23d3d2673b27ca450df))
+* pass extension into the constructor. ([#214](https://www.github.com/lholmquist/sdk-javascript/issues/214)) ([0378f4c](https://www.github.com/lholmquist/sdk-javascript/commit/0378f4cdf9fde647ac3ffe1f9fb6bd3ff0924280)), closes [#209](https://www.github.com/lholmquist/sdk-javascript/issues/209)
+* remove unused plugins ([#262](https://www.github.com/lholmquist/sdk-javascript/issues/262)) ([4014da2](https://www.github.com/lholmquist/sdk-javascript/commit/4014da26f5ae00d8846ab804ba0fb847051c44eb))
+* simplify validation logic/imports ([#265](https://www.github.com/lholmquist/sdk-javascript/issues/265)) ([4b54b27](https://www.github.com/lholmquist/sdk-javascript/commit/4b54b272a5578523c3a03b21720cb89c0d5177db))
+* use npm name cloudevents ([#260](https://www.github.com/lholmquist/sdk-javascript/issues/260)) ([565f867](https://www.github.com/lholmquist/sdk-javascript/commit/565f8674246b5f60ff78141ea9548b4137e2befc)), closes [#215](https://www.github.com/lholmquist/sdk-javascript/issues/215)
+* **src:**  A CloudEvent should be readonly but provide a way to augment itself. ([#234](https://www.github.com/lholmquist/sdk-javascript/issues/234)) ([c7a8477](https://www.github.com/lholmquist/sdk-javascript/commit/c7a84772d59647e2a94991a3051b37b097b0d404))
+* **src:** add ext name validation ([#246](https://www.github.com/lholmquist/sdk-javascript/issues/246)) ([84f1ed9](https://www.github.com/lholmquist/sdk-javascript/commit/84f1ed9cfe54d60978c525de5b0c49cf38839deb))
+* **unmarshaller:** remove asynchronous 0.3 unmarshaller API ([#126](https://www.github.com/lholmquist/sdk-javascript/issues/126)) ([63ae1ad](https://www.github.com/lholmquist/sdk-javascript/commit/63ae1ad527f0b9652222cbc7e51f7a895410a4b4))
+* use CloudEvents not cloudevents everywhere ([#101](https://www.github.com/lholmquist/sdk-javascript/issues/101)) ([05ecbde](https://www.github.com/lholmquist/sdk-javascript/commit/05ecbdea4f594a6012ba7717f3311d0c20c2985f))
+
+
+### Bug Fixes
+
+* Add Correct Headers to emitted Binary Event ([#302](https://www.github.com/lholmquist/sdk-javascript/issues/302)) ([ad0c434](https://www.github.com/lholmquist/sdk-javascript/commit/ad0c4340b2b3cf8a6204f7fb9e1df140092e23c9)), closes [#301](https://www.github.com/lholmquist/sdk-javascript/issues/301)
+* add correct types to improve TypeScript behavior ([#202](https://www.github.com/lholmquist/sdk-javascript/issues/202)) ([da365e0](https://www.github.com/lholmquist/sdk-javascript/commit/da365e09ebcb493f63e6962800230899f1b978ad))
+* do not require an HTTP body on incoming binary event messages ([a7c326b](https://www.github.com/lholmquist/sdk-javascript/commit/a7c326b48cf702a077fc4af1eda3f686429ba9df))
+* ensure binary events can handle no content-type header ([#134](https://www.github.com/lholmquist/sdk-javascript/issues/134)) ([72a87df](https://www.github.com/lholmquist/sdk-javascript/commit/72a87dfb2d05411f9f58b417bbc7db4233dcbbbf))
+* ensure that data encoded as base64 is parsed as an object ([#285](https://www.github.com/lholmquist/sdk-javascript/issues/285)) ([ed9ea95](https://www.github.com/lholmquist/sdk-javascript/commit/ed9ea956d73491cc890751bf1baf4f0be828a9cb))
+* ensure that event data can be an array, number, boolean or null ([#281](https://www.github.com/lholmquist/sdk-javascript/issues/281)) ([b99f728](https://www.github.com/lholmquist/sdk-javascript/commit/b99f7281904b41d9058fec8f51019c5937821dc9))
+* ensure that the HTTP receiver sanitizes headers in accept() ([#239](https://www.github.com/lholmquist/sdk-javascript/issues/239)) ([51035dc](https://www.github.com/lholmquist/sdk-javascript/commit/51035dc65b98ce7912d57a78d214612c05c5dc00))
+* Fix Express example installation ([#77](https://www.github.com/lholmquist/sdk-javascript/issues/77)) ([bb8e0f9](https://www.github.com/lholmquist/sdk-javascript/commit/bb8e0f9e0ca7aef00103d03f6071a648a9fab76d))
+* fix references to constants - remove .js extension ([#200](https://www.github.com/lholmquist/sdk-javascript/issues/200)) ([c757a2b](https://www.github.com/lholmquist/sdk-javascript/commit/c757a2bce1e5432c420db7a4ae4755058964cff7))
+* initialize CloudEvent's extensions property ([#192](https://www.github.com/lholmquist/sdk-javascript/issues/192)) ([0710166](https://www.github.com/lholmquist/sdk-javascript/commit/0710166ce9397f402b835fae745923d11357d15e))
+* introduce CloudEventV1 and CloudEventV03 interfaces ([#194](https://www.github.com/lholmquist/sdk-javascript/issues/194)) ([a5befbe](https://www.github.com/lholmquist/sdk-javascript/commit/a5befbe0cf11a53e39f3ea33990b037e2f165611))
+* make application/json the default content type in binary mode ([#118](https://www.github.com/lholmquist/sdk-javascript/issues/118)) ([d9e9ae6](https://www.github.com/lholmquist/sdk-javascript/commit/d9e9ae6bdcbaf80dc35d486765c9189a176be650))
+* misspelled word ([#113](https://www.github.com/lholmquist/sdk-javascript/issues/113)) ([cd6a3ee](https://www.github.com/lholmquist/sdk-javascript/commit/cd6a3eec7dca4bac1e2ba9fbba9949799e6c97d8))
+* misspelled word ([#115](https://www.github.com/lholmquist/sdk-javascript/issues/115)) ([53524ac](https://www.github.com/lholmquist/sdk-javascript/commit/53524acb0e18598b1376fa4485cdd2a117e892fd))
+* package.json & package-lock.json to reduce vulnerabilities ([#253](https://www.github.com/lholmquist/sdk-javascript/issues/253)) ([2ed5f84](https://www.github.com/lholmquist/sdk-javascript/commit/2ed5f844570efdf3ccc301fd5854fe4100921e04))
+* parse method mutating its input ([#231](https://www.github.com/lholmquist/sdk-javascript/issues/231)) ([060b21b](https://www.github.com/lholmquist/sdk-javascript/commit/060b21ba36a37afc9002fe2e3d2d3b161633f9ae))
+* protects the consts from being changed in other parts of the code. ([fbcbcec](https://www.github.com/lholmquist/sdk-javascript/commit/fbcbcec4e885618367c5cb25a8e030549dd829df))
+* remove d.ts types. Fixes [#83](https://www.github.com/lholmquist/sdk-javascript/issues/83) ([#84](https://www.github.com/lholmquist/sdk-javascript/issues/84)) ([6c223e2](https://www.github.com/lholmquist/sdk-javascript/commit/6c223e2c34769fc0b2f2dbc58a398eb85442af92))
+* throw "no cloud event detected" if one can't be read ([#139](https://www.github.com/lholmquist/sdk-javascript/issues/139)) ([ef7550d](https://www.github.com/lholmquist/sdk-javascript/commit/ef7550d60d248e1720172c0a18ae5dc21e8da5a1))
+* update browser name to cloudevents. ([#292](https://www.github.com/lholmquist/sdk-javascript/issues/292)) ([48d182b](https://www.github.com/lholmquist/sdk-javascript/commit/48d182bc5f3c6f7feb6dec9ce5bb68ff5ad14e66)), closes [#286](https://www.github.com/lholmquist/sdk-javascript/issues/286)
+* upgrade uuid from 8.0.0 to 8.1.0 ([#220](https://www.github.com/lholmquist/sdk-javascript/issues/220)) ([25077a9](https://www.github.com/lholmquist/sdk-javascript/commit/25077a9b43bc2e54cd52266fb664a9c523d3f65c))
+* upgrade uuid from 8.1.0 to 8.2.0 ([#250](https://www.github.com/lholmquist/sdk-javascript/issues/250)) ([13bcdb4](https://www.github.com/lholmquist/sdk-javascript/commit/13bcdb4b9817bcf28991269f554f73893b42b458))
+* use /lib in gitignore so src/lib is not ignored ([#199](https://www.github.com/lholmquist/sdk-javascript/issues/199)) ([fba3294](https://www.github.com/lholmquist/sdk-javascript/commit/fba3294ce04a30be0e5ab551a1fa01727dc8d1f8))
+
+
+### lib
+
+* change CloudEvent to use direct object notation and get/set properties ([#172](https://www.github.com/lholmquist/sdk-javascript/issues/172)) ([abc114b](https://www.github.com/lholmquist/sdk-javascript/commit/abc114b24e448a33d2a4f583cdc7ae191940bdca))
+* refactor HTTP bindings and specifications ([#165](https://www.github.com/lholmquist/sdk-javascript/issues/165)) ([6f0b5ea](https://www.github.com/lholmquist/sdk-javascript/commit/6f0b5ea5f11ae8a451df2c46208bbd1e08ff7227))
+* validate extension values ([#251](https://www.github.com/lholmquist/sdk-javascript/issues/251)) ([3c8273f](https://www.github.com/lholmquist/sdk-javascript/commit/3c8273f1140455ce8346918942c44dda241ead4c))
+
 ### [3.0.1](https://github.com/cloudevents/sdk-javascript/compare/v3.0.0...v3.0.1) (2020-07-29)
 
 
diff --git a/package.json b/package.json
index fcb1b47e..1f4cf643 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cloudevents",
-  "version": "3.0.1",
+  "version": "4.0.0",
   "description": "CloudEvents SDK for JavaScript",
   "main": "dist/index.js",
   "scripts": {