Index: branches/4.4/.travis.yml
===================================================================
--- branches/4.4/.travis.yml	(revision 37754)
+++ branches/4.4/.travis.yml	(working copy)
@@ -27,6 +27,11 @@
   - php: hhvm
   - php: nightly
 before_install:
+- npm --version
+- node --version
+- nvm install 4
+- npm --version
+- node --version
 - WP_CORE_DIR=/tmp/wordpress/
 - git clone https://github.com/WordPress/twentysixteen.git src/wp-content/themes/twentysixteen
 - |
@@ -47,8 +52,6 @@
 - npm install -g npm
 - npm install -g grunt-cli
 - npm install
-- npm --version
-- node --version
 script: grunt $WP_TRAVISCI
 notifications:
   slack:
Index: branches/4.4/package.json
===================================================================
--- branches/4.4/package.json	(revision 37754)
+++ branches/4.4/package.json	(working copy)
@@ -8,6 +8,9 @@
   },
   "author": "The WordPress Contributors",
   "license": "GPL-2.0+",
+  "engines": {
+    "node": ">=4.2.1"
+  },
   "devDependencies": {
     "autoprefixer": "~6.1.0",
     "grunt": "~0.4.5",
Index: branches/4.5/.travis.yml
===================================================================
--- branches/4.5/.travis.yml	(revision 37754)
+++ branches/4.5/.travis.yml	(working copy)
@@ -30,6 +30,11 @@
   - php: hhvm
   - php: nightly
 before_install:
+- npm --version
+- node --version
+- nvm install 4
+- npm --version
+- node --version
 - WP_CORE_DIR=/tmp/wordpress/
 - git clone https://github.com/WordPress/twentysixteen.git src/wp-content/themes/twentysixteen
 - |
@@ -50,8 +55,6 @@
 - npm install -g npm
 - npm install -g grunt-cli
 - npm install
-- npm --version
-- node --version
 script: grunt $WP_TRAVISCI
 notifications:
   slack:
Index: branches/4.5/package.json
===================================================================
--- branches/4.5/package.json	(revision 37754)
+++ branches/4.5/package.json	(working copy)
@@ -8,6 +8,9 @@
   },
   "author": "The WordPress Contributors",
   "license": "GPL-2.0+",
+  "engines": {
+    "node": ">=4.2.1"
+  },
   "devDependencies": {
     "autoprefixer": "~6.3.3",
     "git-or-svn": "~0.1.0",
Index: trunk/.travis.yml
===================================================================
--- trunk/.travis.yml	(revision 37754)
+++ trunk/.travis.yml	(working copy)
@@ -35,6 +35,13 @@
   - php: hhvm
   - php: nightly
 before_install:
+- mysql --version
+- phpenv versions
+- npm --version
+- node --version
+- nvm install 4
+- npm --version
+- node --version
 - git clone https://github.com/WordPress/twentysixteen.git src/wp-content/themes/twentysixteen
 - |
   if [[ "$WP_TRAVISCI" == "travis:phpunit" ]]; then
@@ -55,10 +62,6 @@
 - npm install -g grunt-cli
 - npm install
 - npm prune
-- mysql --version
-- phpenv versions
-- npm --version
-- node --version
 script: grunt $WP_TRAVISCI
 notifications:
   slack:
Index: trunk/package.json
===================================================================
--- trunk/package.json	(revision 37754)
+++ trunk/package.json	(working copy)
@@ -8,6 +8,9 @@
   },
   "author": "The WordPress Contributors",
   "license": "GPL-2.0+",
+  "engines": {
+    "node": ">=4.2.1"
+  },
   "devDependencies": {
     "autoprefixer": "~6.3.3",
     "grunt": "~0.4.5",