diff --git a/doc/api.md b/doc/api.md
index 87e25315..0c158838 100644
--- a/doc/api.md
+++ b/doc/api.md
@@ -5,7 +5,7 @@ layout: api
 ---
 
 
-The following API reference is for **SPF 23 (v2.3.2)**.
+The following API reference is for **SPF 24 (v2.4.0)**.
 
 
 * * *
@@ -173,7 +173,7 @@ The string "multipart".
 Definition for options when requesting a URL.
 
 **Attributes**  
-`experimental_headers: Object.<string> | undefined`  
+`headers: Object.<string> | undefined`  
 Optional map of headers to send with the request.  
 `method: string | undefined`  
 Optional method with which to send the request; defaults to "GET".  
@@ -260,6 +260,8 @@ The URL of the previous page; defined for "spfhistory" and
 A complete SPF response; defined for "spfprocess" events as a single
 response and for "spfdone" events as either a single or multipart
 response (see [spf.SingleResponse](#spf.singleresponse) and [spf.MultipartResponse](#spf.multipartresponse).  
+`xhr: XMLHttpRequest | undefined`  
+A complete XMLHttpRequest object; defined for "onError" events.  
 `target: Element | undefined`  
 The target element of a click; defined for "spfclick" events.  
 `url: string | undefined`  
diff --git a/doc/download.md b/doc/download.md
index 4e2d72ba..cab500cc 100644
--- a/doc/download.md
+++ b/doc/download.md
@@ -25,31 +25,31 @@ bower install spf
 You can link to the JS files directly from several popular CDNs:
 
 - [Google Hosted Libraries][]  
-  `https://ajax.googleapis.com/ajax/libs/spf/2.3.2/spf.js`
+  `https://ajax.googleapis.com/ajax/libs/spf/2.4.0/spf.js`
 - [cdnjs][]  
-  `https://cdnjs.cloudflare.com/ajax/libs/spf/2.3.2/spf.js`
+  `https://cdnjs.cloudflare.com/ajax/libs/spf/2.4.0/spf.js`
 - [jsDelivr][]  
-  `https://cdn.jsdelivr.net/spf/2.3.2/spf.js`
+  `https://cdn.jsdelivr.net/spf/2.4.0/spf.js`
 - [OSSCDN][]  
-  `https://oss.maxcdn.com/spf/2.3.2/spf.js`
+  `https://oss.maxcdn.com/spf/2.4.0/spf.js`
 
 
 ## Download a release
 
 Download just the minified JS files:
-**[spfjs-2.3.2-dist.zip][spfjs-dist-zip]**
+**[spfjs-2.4.0-dist.zip][spfjs-dist-zip]**
 
 ```sh
-curl -LO https://github.com/youtube/spfjs/releases/download/v2.3.2/spfjs-2.3.2-dist.zip
-unzip spfjs-2.3.2-dist.zip
+curl -LO https://github.com/youtube/spfjs/releases/download/v2.4.0/spfjs-2.4.0-dist.zip
+unzip spfjs-2.4.0-dist.zip
 ```
 
 Or, download the minified files and complete source code:
-**[v2.3.2.zip][spfjs-src-zip]**
+**[v2.4.0.zip][spfjs-src-zip]**
 
 ```sh
-curl -LO https://github.com/youtube/spfjs/archive/v2.3.2.zip
-unzip v2.3.2.zip
+curl -LO https://github.com/youtube/spfjs/archive/v2.4.0.zip
+unzip v2.4.0.zip
 ```
 
 
@@ -60,7 +60,7 @@ Clone the project from GitHub and checkout the release:
 ```sh
 git clone https://github.com/youtube/spfjs.git
 cd spfjs
-git checkout v2.3.2
+git checkout v2.4.0
 ```
 
 
@@ -77,5 +77,5 @@ After you've grabbed the code, **[get started][]**.
 [cdnjs]: https://cdnjs.com/libraries/spf
 [jsDelivr]: http://www.jsdelivr.com/#!spf
 [OSSCDN]: http://osscdn.com/#/spf
-[spfjs-dist-zip]: https://github.com/youtube/spfjs/releases/download/v2.3.2/spfjs-2.3.2-dist.zip
-[spfjs-src-zip]: https://github.com/youtube/spfjs/archive/v2.3.2.zip
+[spfjs-dist-zip]: https://github.com/youtube/spfjs/releases/download/v2.4.0/spfjs-2.4.0-dist.zip
+[spfjs-src-zip]: https://github.com/youtube/spfjs/archive/v2.4.0.zip
diff --git a/package.json b/package.json
index 03c27201..b95ccc2a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "spf",
-  "version": "2.3.2",
+  "version": "2.4.0",
   "description": "A lightweight JS framework for fast navigation and page updates from YouTube",
   "license": "MIT",
   "homepage": "https://github.com/youtube/spfjs",
diff --git a/web/config.yml b/web/config.yml
index d740c956..7588d239 100644
--- a/web/config.yml
+++ b/web/config.yml
@@ -9,8 +9,8 @@ baseurl: /spfjs
 title: SPF
 description: A lightweight JS framework for fast navigation and page updates from YouTube
 
-release: SPF 23 (v2.3.2)
-version: 2.3.2
+release: SPF 24 (v2.4.0)
+version: 2.4.0
 
 exclude:
   - Gemfile