Upgrade to Babel 6.

.babelrc

@@ -1,15 +1,12 @@
 {
   "comments": false,
   "compact": true,
-  "optional": [
-    // Experimental features.
-    // "minification.constantFolding",
-    // "minification.deadCodeElimination",
-
-    "es7.asyncFunctions",
-    "es7.decorators",
-    "es7.exportExtensions",
-    "es7.functionBind",
-    "runtime"
+  "plugins": [
+    "transform-decorators-legacy",
+    "transform-runtime"
+  ],
+  "presets": [
+    "stage-0",
+    "es2015"
   ]
 }

package.json

@@ -36,7 +36,7 @@
   "dependencies": {
     "@marsaud/smb2-promise": "^0.1.0",
     "app-conf": "^0.4.0",
-    "babel-runtime": "^5",
+    "babel-runtime": "^6.5.0",
     "base64url": "^1.0.5",
     "blocked": "^1.1.0",
     "bluebird": "^3.1.1",
@@ -132,11 +132,15 @@
     "xo-remote-parser": "^0.1.0"
   },
   "devDependencies": {
-    "babel-eslint": "^4.0.10",
+    "babel-eslint": "^5.0.0",
+    "babel-plugin-transform-decorators-legacy": "^1.3.4",
+    "babel-plugin-transform-runtime": "^6.5.2",
+    "babel-preset-es2015": "^6.5.0",
+    "babel-preset-stage-0": "^6.5.0",
     "chai": "^3.0.0",
     "dependency-check": "^2.4.0",
     "gulp": "git://github.com/gulpjs/gulp#4.0",
-    "gulp-babel": "^5",
+    "gulp-babel": "^6",
     "gulp-coffee": "^2.3.1",
     "gulp-plumber": "^1.0.0",
     "gulp-sourcemaps": "^1.5.1",