diff --git a/packages/gatsby-plugin-offline/src/gatsby-browser.js b/packages/gatsby-plugin-offline/src/gatsby-browser.js
index 8285b08d6bcb2..a74e3aaf3ba94 100644
--- a/packages/gatsby-plugin-offline/src/gatsby-browser.js
+++ b/packages/gatsby-plugin-offline/src/gatsby-browser.js
@@ -107,3 +107,14 @@ exports.onRouteUpdate = ({ location, getResourceURLsForPathname }) => {
 exports.onPostPrefetchPathname = ({ pathname, getResourceURLsForPathname }) => {
   setPathResources(pathname, getResourceURLsForPathname)
 }
+
+export const onServiceWorkerUpdateReady = () => {
+  const answer = window.confirm(
+    `This application has been updated. ` +
+      `Reload to display the latest version?`
+  )
+
+  if (answer === true) {
+    window.location.reload()
+  }
+}
diff --git a/packages/gatsby-plugin-offline/src/gatsby-node.js b/packages/gatsby-plugin-offline/src/gatsby-node.js
index a392d03412f0d..4c959e6c47743 100644
--- a/packages/gatsby-plugin-offline/src/gatsby-node.js
+++ b/packages/gatsby-plugin-offline/src/gatsby-node.js
@@ -1,13 +1,11 @@
-// use `let` to workaround https://github.com/jhnns/rewire/issues/144
-/* eslint-disable prefer-const */
-let fs = require(`fs`)
-let workboxBuild = require(`workbox-build`)
+const fs = require(`fs`)
+const workboxBuild = require(`workbox-build`)
 const path = require(`path`)
 const { slash } = require(`gatsby-core-utils`)
 const glob = require(`glob`)
 const _ = require(`lodash`)
 
-let getResourcesFromHTML = require(`./get-resources-from-html`)
+const getResourcesFromHTML = require(`./get-resources-from-html`)
 
 exports.onPreBootstrap = ({ cache }) => {
   const appShellSourcePath = path.join(__dirname, `app-shell.js`)
@@ -220,49 +218,3 @@ exports.onPostBuild = (
       )
     })
 }
-
-const MATCH_ALL_KEYS = /^/
-exports.pluginOptionsSchema = function ({ Joi }) {
-  // These are the options of the v3: https://www.gatsbyjs.com/plugins/gatsby-plugin-offline/#available-options
-  return Joi.object({
-    precachePages: Joi.array()
-      .items(Joi.string())
-      .description(
-        `An array of pages whose resources should be precached by the service worker, using an array of globs`
-      ),
-    appendScript: Joi.string().description(
-      `A file (path) to be appended at the end of the generated service worker`
-    ),
-    debug: Joi.boolean().description(
-      `Specifies whether Workbox should show debugging output in the browser console at runtime. When undefined, defaults to showing debug messages on localhost only`
-    ),
-    workboxConfig: Joi.object({
-      importWorkboxFrom: Joi.string(),
-      globDirectory: Joi.string(),
-      globPatterns: Joi.array().items(Joi.string()),
-      modifyURLPrefix: Joi.object().pattern(MATCH_ALL_KEYS, Joi.string()),
-      cacheId: Joi.string(),
-      dontCacheBustURLsMatching: Joi.object().instance(RegExp),
-      maximumFileSizeToCacheInBytes: Joi.number(),
-      runtimeCaching: Joi.array().items(
-        Joi.object({
-          urlPattern: Joi.object().instance(RegExp),
-          handler: Joi.string().valid(
-            `StaleWhileRevalidate`,
-            `CacheFirst`,
-            `NetworkFirst`,
-            `NetworkOnly`,
-            `CacheOnly`
-          ),
-          options: Joi.object({
-            networkTimeoutSeconds: Joi.number(),
-          }),
-        })
-      ),
-      skipWaiting: Joi.boolean(),
-      clientsClaim: Joi.boolean(),
-    })
-      .description(`Overrides workbox configuration. Helpful documentation: https://www.gatsbyjs.com/plugins/gatsby-plugin-offline/#overriding-workbox-configuration
-      `),
-  })
-}