“Task function must be specified at Gulp.set” error when running gulp

It seems to be related to the Gulp V4, there’s two options:

• Update your code to V4 (Article related )

OR

• Downgrade gulp version

To downgrade you need to update your package.json with

"gulp": "^3.9.1",

And then remove node_module folder and reinstall npm packages

rm -rf node_modules
npm install