• Breaking change: all options passed to the server get validated now, just like the webpack options already are. In most cases this shouldn't break anything, but it is possible we missed some valid usages (#654).
• webpack 2.1.0-beta.26 or higher is required.
• If no port is specified, the CLI will now find the first available port that is not in use instead of crashing when port 8080 is in use (#685).
• When the webpack compiler threw an error or warning, the page would be reloaded. Now, it doesn't reload the page (#209).
• The startup information that denotes the URL, path etc. is more fancy now and uses colors (#681).
• Fix --version flag not working in CLI (#679).
• Fix --open flag opening the wrong URL when using lazy mode (7cb0490).
• Compilation errors were duplicated in the DevTools (webpack/webpack#3008).
• Expose events to the page, so e.g. plugins can show a custom error modal in the browser (#481).