ionic.config.js

// Ionic CLI is no longer responsible for building your web assets, and now
// relies on gulp hooks instead. This file was used for exposing web build
// configuration and is no longer necessary.
// If this file is executed when running ionic commands, then an update to the
// CLI is needed.
//
// If your version of the Ionic CLI is beta.21 or greater, you can delete this file.
console.log('\nFrom ionic.config.js:');
console.log('\nPlease update your version of the Ionic CLI:');
console.log('    npm install -g ionic@beta\n');
process.exit(1);