gulp --version CLI version: 2.3.0 Local version: 4.0.2 code example
Example: gulp downgrade to 3
npm install -g n
sudo n 11.15.0
npm install gulp@^3.9.1
npm install
npm rebuild node-sass
npm install -g n
sudo n 11.15.0
npm install gulp@^3.9.1
npm install
npm rebuild node-sass