Spike v1 represents a significant change, mostly because it includes an update from webpack v1 to webpack v2 behind the scenes. The aim of this piece is to guide you through the process of migration from one version to the next, and explain a bit of the rationale behind these changes.
The bulk of the migration work lies in the app.js file. Webpack drastically changed its configuration in a very breaking manner between v1 and v2, so spike was forced to do the same, since spike is an extension of webpack.