• Polyfill default promise with finally if it doesn't exist if you use polyfill.js
• If using require with webpack 2+, you now need to do

var Promise = require('promise-polyfill').default;

instead of

var Promise = require('promise-polyfill');

• Removed files /dist/promise.js and /dist/promise.min.js. These files were not used unless you downloaded them directly from the repo. They were not used by ES6 modules, CommonJS or polyfill.js The file lead to issues because they overrode the global Promise by default.