Index: Gruntfile.js
===================================================================
--- Gruntfile.js	(revision 33000)
+++ Gruntfile.js	(working copy)
@@ -4,7 +4,8 @@
 		SOURCE_DIR = 'src/',
 		BUILD_DIR = 'build/',
 		mediaConfig = {},
-		mediaBuilds = ['audiovideo', 'grid', 'models', 'views'];
+		mediaBuilds = ['audiovideo', 'grid', 'models', 'views'],
+		autoprefixer = require('autoprefixer-core');
 
 	// Load tasks.
 	require('matchdep').filterDev(['grunt-*', '!grunt-legacy-util']).forEach( grunt.loadNpmTasks );
@@ -19,10 +20,14 @@
 
 	// Project configuration.
 	grunt.initConfig({
-		autoprefixer: {
+		postcss: {
 			options: {
-				browsers: ['Android >= 2.1', 'Chrome >= 21', 'Explorer >= 7', 'Firefox >= 17', 'Opera >= 12.1', 'Safari >= 6.0'],
-				cascade: false
+				processors: [
+					autoprefixer({
+						browsers: ['Android >= 2.1', 'Chrome >= 21', 'Explorer >= 7', 'Firefox >= 17', 'Opera >= 12.1', 'Safari >= 6.0'],
+						cascade: false
+					})
+				]
 			},
 			core: {
 				expand: true,
@@ -577,7 +582,7 @@
 	grunt.registerTask('rtl', ['rtlcss:core', 'rtlcss:colors']);
 
 	// Color schemes task.
-	grunt.registerTask('colors', ['sass:colors', 'autoprefixer:colors']);
+	grunt.registerTask('colors', ['sass:colors', 'postcss:colors']);
 
 	// JSHint task.
 	grunt.registerTask( 'jshint:corejs', [
@@ -606,7 +611,7 @@
 	} );
 
 	grunt.registerTask( 'precommit', 'Runs front-end dev/test tasks in preparation for a commit.', [
-		'autoprefixer:core',
+		'postcss:core',
 		'imagemin:core',
 		'browserify',
 		'jshint:corejs',
Index: package.json
===================================================================
--- package.json	(revision 33000)
+++ package.json	(working copy)
@@ -9,8 +9,8 @@
   "author": "The WordPress Contributors",
   "license": "GPL-2.0+",
   "devDependencies": {
+    "autoprefixer-core": "~5.2.1",
     "grunt": "~0.4.5",
-    "grunt-autoprefixer": "~3.0.0",
     "grunt-browserify": "~3.8.0",
     "grunt-contrib-clean": "~0.6.0",
     "grunt-contrib-compress": "~0.13.0",
@@ -26,6 +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-rtlcss": "~1.6.0",
     "grunt-sass": "~1.0.0",
     "matchdep": "~0.3.0"