diff --git a/Gruntfile.js b/Gruntfile.js
index a56af00967..58f7e211b9 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -154,7 +154,8 @@ module.exports = function(grunt) {
 		},
 		cssmin: {
 			options: {
-				'wp-admin': ['wp-admin', 'color-picker', 'customize-controls', 'customize-widgets', 'customize-nav-menus', 'ie', 'install', 'login', 'press-this', 'deprecated-*']
+				'wp-admin': ['wp-admin', 'color-picker', 'customize-controls', 'customize-widgets', 'customize-nav-menus', 'ie', 'install', 'login', 'press-this', 'deprecated-*'],
+				compatibility: 'ie7'
 			},
 			core: {
 				expand: true,