Index: Gruntfile.js
===================================================================
--- Gruntfile.js	(revision 35290)
+++ Gruntfile.js	(working copy)
@@ -3,7 +3,7 @@
 	var path = require('path'),
 		SOURCE_DIR = 'src/',
 		BUILD_DIR = 'build/',
-		autoprefixer = require('autoprefixer-core'),
+		autoprefixer = require('autoprefixer'),
 		mediaConfig = {},
 		mediaBuilds = ['audiovideo', 'grid', 'models', 'views'];
 
Index: package.json
===================================================================
--- package.json	(revision 35290)
+++ package.json	(working copy)
@@ -9,7 +9,7 @@
   "author": "The WordPress Contributors",
   "license": "GPL-2.0+",
   "devDependencies": {
-    "autoprefixer-core": "~5.2.1",
+    "autoprefixer": "~6.0.3",
     "grunt": "~0.4.5",
     "grunt-browserify": "~4.0.0",
     "grunt-contrib-clean": "~0.6.0",
@@ -26,7 +26,7 @@
     "grunt-jsvalidate": "~0.2.2",
     "grunt-legacy-util": "^0.2.0",
     "grunt-patch-wordpress": "~0.3.0",
-    "grunt-postcss": "~0.5.4",
+    "grunt-postcss": "~0.6.0",
     "grunt-rtlcss": "~1.6.0",
     "grunt-sass": "~1.0.0",
     "matchdep": "~0.3.0"