.npm-upgrade.json

{
  "ignore": {
    "mobx": {
      "versions": ">=6",
      "reason": "v6 drops decorators"
    },
    "mobx-react": {
      "versions": ">=7",
      "reason": "v7 requires MobX v6"
    },
    "webpack-cli": {
      "versions": ">=4",
      "reason": "Current version of Webpack Dev Server doesn't work with v4"
    }
  }
}