diff --git a/.npmignore b/.npmignore
index 71d8676..80a8117 100644
--- a/.npmignore
+++ b/.npmignore
@@ -7,7 +7,5 @@ CVS/
 *.bak
 .DS_Store
 npm-debug.log
-test/
-src/
+test.js
 CHANGELOG.md
-
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b62ccca..e09016b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# jade-brunch 1.7.4 (16 december 2013)
+* New runtime.
+
 # jade-brunch 1.7.3 (20 November 2013)
 * Support watching of plain-html partials referenced in jade source files.
 
diff --git a/package.json b/package.json
index d531c3f..f9bbeb5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "jade-brunch",
-  "version": "1.7.3",
+  "version": "1.7.4",
   "description": "Adds Jade support to brunch.",
   "author": "Paul Miller (http://paulmillr.com/)",
   "homepage": "https://github.com/brunch/jade-brunch",
diff --git a/vendor/runtime.js b/vendor/runtime.js
index 0f54907..83b05ee 100644
--- a/vendor/runtime.js
+++ b/vendor/runtime.js
@@ -1,5 +1,6 @@
+(function(e){if("function"==typeof bootstrap)bootstrap("jade",e);else if("object"==typeof exports)module.exports=e();else if("function"==typeof define&&define.amd)define(e);else if("undefined"!=typeof ses){if(!ses.ok())return;ses.makeJade=e}else"undefined"!=typeof window?window.jade=e():global.jade=e()})(function(){var define,ses,bootstrap,module,exports;
+return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);throw new Error("Cannot find module '"+o+"'")}var f=n[o]={exports:{}};t[o][0].call(f.exports,function(e){var n=t[o][1][e];return s(n?n:e)},f,f.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
 
-jade = (function(exports){
 /*!
  * Jade - runtime
  * Copyright(c) 2010 TJ Holowaychuk <tj@vision-media.ca>
@@ -53,9 +54,7 @@ exports.merge = function merge(a, b) {
     bc = bc || [];
     if (!Array.isArray(ac)) ac = [ac];
     if (!Array.isArray(bc)) bc = [bc];
-    ac = ac.filter(nulls);
-    bc = bc.filter(nulls);
-    a['class'] = ac.concat(bc).join(' ');
+    a['class'] = ac.concat(bc).filter(nulls);
   }
 
   for (var key in b) {
@@ -70,13 +69,25 @@ exports.merge = function merge(a, b) {
 /**
  * Filter null `val`s.
  *
- * @param {Mixed} val
- * @return {Mixed}
+ * @param {*} val
+ * @return {Boolean}
  * @api private
  */
 
 function nulls(val) {
-  return val != null;
+  return val != null && val !== '';
+}
+
+/**
+ * join array as classes.
+ *
+ * @param {*} val
+ * @return {String}
+ * @api private
+ */
+
+function joinClasses(val) {
+  return Array.isArray(val) ? val.map(joinClasses).filter(nulls).join(' ') : val;
 }
 
 /**
@@ -110,8 +121,16 @@ exports.attrs = function attrs(obj, escaped){
         }
       } else if (0 == key.indexOf('data') && 'string' != typeof val) {
         buf.push(key + "='" + JSON.stringify(val) + "'");
-      } else if ('class' == key && Array.isArray(val)) {
-        buf.push(key + '="' + exports.escape(val.join(' ')) + '"');
+      } else if ('class' == key) {
+        if (escaped && escaped[key]){
+          if (val = exports.escape(joinClasses(val))) {
+            buf.push(key + '="' + val + '"');
+          }
+        } else {
+          if (val = joinClasses(val)) {
+            buf.push(key + '="' + val + '"');
+          }
+        }
       } else if (escaped && escaped[key]) {
         buf.push(key + '="' + exports.escape(val) + '"');
       } else {
@@ -133,7 +152,7 @@ exports.attrs = function attrs(obj, escaped){
 
 exports.escape = function escape(html){
   return String(html)
-    .replace(/&(?!(\w+|\#\d+);)/g, '&amp;')
+    .replace(/&/g, '&amp;')
     .replace(/</g, '&lt;')
     .replace(/>/g, '&gt;')
     .replace(/"/g, '&quot;');
@@ -149,11 +168,18 @@ exports.escape = function escape(html){
  * @api private
  */
 
-exports.rethrow = function rethrow(err, filename, lineno){
-  if (!filename) throw err;
-
+exports.rethrow = function rethrow(err, filename, lineno, str){
+  if (!(err instanceof Error)) throw err;
+  if ((typeof window != 'undefined' || !filename) && !str) {
+    err.message += ' on line ' + lineno;
+    throw err;
+  }
+  try {
+    str =  str || require('fs').readFileSync(filename, 'utf8')
+  } catch (ex) {
+    rethrow(err, null, lineno)
+  }
   var context = 3
-    , str = require('fs').readFileSync(filename, 'utf8')
     , lines = str.split('\n')
     , start = Math.max(lineno - context, 0)
     , end = Math.min(lines.length, lineno + context);
@@ -174,6 +200,9 @@ exports.rethrow = function rethrow(err, filename, lineno){
   throw err;
 };
 
-  return exports;
+},{"fs":2}],2:[function(require,module,exports){
+// nothing to see here... no file methods for the browser
 
-})({});
+},{}]},{},[1])(1)
+});
+;