v3 to v4 Migration Guide
v4.0.0 Migration Guide
FYI: v4 drops support for Node 6 and 7. If you need support for versions of Node that have reached EOL, please use v3.
Node.js API
There is a new Node.js API available. Please see the docs.
package.json configuration property name change
It is possible to specify configuration in your package.json file. In v3, the property name was npmPackageJsonLintConfig. This must be changed to npmpackagejsonlint in v4.
Additional changes
Please see the release notes for additional changes introduced in v4.0.0.