diff --git a/package.json b/package.json
index 87b80bd..712819c 100755
--- a/package.json
+++ b/package.json
@@ -8,15 +8,15 @@
     "url": "https://github.com/KorAP/Kalamar.git"
   },
   "devDependencies": {
-    "grunt":                   "^0.4.5",
-    "grunt-contrib-copy":      "^0.8.0",
-    "grunt-contrib-imagemin":  "^1.0.0",
-    "imagemin":                "^4.0.0",
-    "grunt-contrib-jasmine":   "^0.8.2",
-    "grunt-contrib-sass":      "^0.9.2",
-    "grunt-contrib-watch":     "^0.6.1",
-    "grunt-contrib-requirejs": "^0.4.4",
-    "vinyl-fs":                "^2.1.1",
-    "optipng-bin":             "^3.1.2"
+    "grunt":                   "^1.0.1",
+    "grunt-contrib-copy":      "^1.0.0",
+    "grunt-contrib-imagemin":  "^2.0.1",
+    "imagemin":                "^5.3.1",
+    "grunt-contrib-jasmine":   "^1.1.0",
+    "grunt-contrib-sass":      "^1.0.0",
+    "grunt-contrib-watch":     "^1.0.0",
+    "grunt-contrib-requirejs": "^1.0.0",
+    "vinyl-fs":                "^3.0.2",
+    "optipng-bin":             "^4.0.0"
   }
 }