diff --git a/CHANGELOG.md b/CHANGELOG.md
index 561f91e..7b7da89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# Exoskeleton 0.5.1 (3 November 2013)
+* Added support for `contentType` option in `utils.ajax`
+
 # Exoskeleton 0.5.0 (2 November 2013)
 * Fixed behaviour in node.js environment.
 * `Backbone.Deferred` now must return actual `Deferred`
diff --git a/bower.json b/bower.json
index 8b09ef2..358f294 100644
--- a/bower.json
+++ b/bower.json
@@ -1,7 +1,7 @@
 {
   "name": "exoskeleton",
   "main": "exoskeleton.js",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "homepage": "https://github.com/paulmillr/exoskeleton",
   "author": "Paul Miller (http://paulmillr.com)",
   "description": "Faster and leaner Backbone for your HTML5 apps.",
diff --git a/component.json b/component.json
index 9686dd8..e946b44 100644
--- a/component.json
+++ b/component.json
@@ -2,7 +2,7 @@
   "name": "exoskeleton",
   "repo": "paulmillr/exoskeleton",
   "description": "Faster and leaner Backbone for your HTML5 apps.",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "keywords": [
     "Backbone",
     "Exoskeleton",
diff --git a/exoskeleton.js b/exoskeleton.js
index ec1a5ed..ebfff8e 100644
--- a/exoskeleton.js
+++ b/exoskeleton.js
@@ -1,5 +1,5 @@
 /*!
- * Exoskeleton.js 0.5.0
+ * Exoskeleton.js 0.5.1
  * (c) 2013 Paul Miller <http://paulmillr.com>
  * Based on Backbone.js
  * (c) 2010-2013 Jeremy Ashkenas, DocumentCloud
@@ -369,6 +369,10 @@ utils.ajax = (function() {
     var xhr = new XMLHttpRequest();
     var deferred = Backbone.Deferred && Backbone.Deferred();
 
+    if (options.contentType) {
+      if (options.headers == null) options.headers = {};
+      options.headers['Content-Type'] = options.contentType;
+    }
     if (options.credentials) options.withCredentials = true;
     xhr.addEventListener('readystatechange', end(xhr, options, deferred));
     xhr.open(options.type, options.url, true);
@@ -434,7 +438,7 @@ var Events = Backbone.Events = {
     if (!this._events || !eventsApi(this, 'off', name, [callback, context]))
       return this;
     if (!name && !callback && !context) {
-      delete this._events;
+      this._events = undefined;
       return this;
     }
 
diff --git a/lib/header.js b/lib/header.js
index 9aa648e..b2c7495 100644
--- a/lib/header.js
+++ b/lib/header.js
@@ -1,5 +1,5 @@
 /*!
- * Exoskeleton.js 0.5.0
+ * Exoskeleton.js 0.5.1
  * (c) 2013 Paul Miller <http://paulmillr.com>
  * Based on Backbone.js
  * (c) 2010-2013 Jeremy Ashkenas, DocumentCloud
diff --git a/package.json b/package.json
index 5be5212..6c781ef 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "exoskeleton",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "Faster and leaner Backbone for your HTML5 apps.",
   "main": "exoskeleton.js",
   "directories": {