diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9d7f3e8..2dcb05f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,11 @@
 
 All notable changes to `laravel-sitemap` will be documented in this file
 
-## 4.0.0 - 2018-08-02
+## 5.0.0 - 2018-03-02
+
+- Update to Crawler 4.0
+
+## 4.0.0 - 2018-02-08
 
 - Update to Laravel 5.6
 - Update to phpunit 7
diff --git a/README.md b/README.md
index bdae9da..428b43c 100644
--- a/README.md
+++ b/README.md
@@ -174,7 +174,7 @@ You can create a custom crawl profile by implementing the `Spatie\Crawler\CrawlP
 use Spatie\Crawler\Url;
 use Spatie\Crawler\CrawlProfile;
 
-class CustomCrawlProfile implements CrawlProfile
+class CustomCrawlProfile extends CrawlProfile
 {
     /**
      * Determine if the given url should be crawled.
diff --git a/UPGRADING.md b/UPGRADING.md
index 1b5112f..cc6f321 100644
--- a/UPGRADING.md
+++ b/UPGRADING.md
@@ -2,6 +2,10 @@
 
 Because there are many breaking changes an upgrade is not that easy. There are many edge cases this guide does not cover. We accept PRs to improve this guide.
 
+## From 4.0 to 5.0
+
+- `spatie/crawler` is updated to `^4.0`. This version made changes to the way custom `Profiles` and `Observers` are made. Please see the [UPGRADING](https://github.com/spatie/crawler/blob/master/UPGRADING.md) guide of `spatie/crawler` to know how to update any custom crawl profiles or observers - if you have any.
+
 ## From 3.0 to 4.0
 
 - `spatie/crawler` is updated to `^3.0`. This version introduced the use of PSR-7 `UriInterface` instead of a custom `Url` class. Please see the [UPGRADING](https://github.com/spatie/crawler/blob/master/UPGRADING.md) guide of `spatie/crawler` to know how to update any custom crawl profiles - if you have any.
diff --git a/composer.json b/composer.json
index 10f4c6d..b84a667 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
         "php": "^7.1",
         "illuminate/support": "~5.5.0|~5.6.0",
         "nesbot/carbon": "^1.21",
-        "spatie/crawler": "^3.0",
+        "spatie/crawler": "^4.0",
         "spatie/temporary-directory": "^1.1"
     },
     "require-dev": {
diff --git a/src/Crawler/Observer.php b/src/Crawler/Observer.php
index bfac41c..6e40012 100644
--- a/src/Crawler/Observer.php
+++ b/src/Crawler/Observer.php
@@ -2,10 +2,12 @@
 
 namespace Spatie\Sitemap\Crawler;
 
+use GuzzleHttp\Exception\RequestException;
+use Psr\Http\Message\ResponseInterface;
 use Spatie\Crawler\CrawlObserver;
 use Psr\Http\Message\UriInterface;
 
-class Observer implements CrawlObserver
+class Observer extends CrawlObserver
 {
     /** @var callable */
     protected $hasCrawled;
@@ -25,21 +27,39 @@ public function willCrawl(UriInterface $url)
     }
 
     /**
-     * Called when the crawler has crawled the given url.
-     *
-     * @param \Psr\Http\Message\UriInterface $url
-     * @param \Psr\Http\Message\ResponseInterface|null $response
-     * @param \Psr\Http\Message\UriInterface $foundOnUrl
+     * Called when the crawl has ended.
      */
-    public function hasBeenCrawled(UriInterface $url, $response, ?UriInterface $foundOnUrl = null)
+    public function finishedCrawling()
     {
+    }
+
+    /**
+     * Called when the crawler has crawled the given url successfully.
+     *
+     * @param \Psr\Http\Message\UriInterface      $url
+     * @param \Psr\Http\Message\ResponseInterface $response
+     * @param \Psr\Http\Message\UriInterface|null $foundOnUrl
+     */
+    public function crawled(
+        UriInterface $url,
+        ResponseInterface $response,
+        ?UriInterface $foundOnUrl = null
+    ) {
         ($this->hasCrawled)($url, $response);
     }
 
     /**
-     * Called when the crawl has ended.
+     * Called when the crawler had a problem crawling the given url.
+     *
+     * @param \Psr\Http\Message\UriInterface         $url
+     * @param \GuzzleHttp\Exception\RequestException $requestException
+     * @param \Psr\Http\Message\UriInterface|null    $foundOnUrl
      */
-    public function finishedCrawling()
-    {
+    public function crawlFailed(
+        UriInterface $url,
+        RequestException $requestException,
+        ?UriInterface $foundOnUrl = null
+    ) {
+        return;
     }
 }
diff --git a/src/Crawler/Profile.php b/src/Crawler/Profile.php
index 31b5cef..ff041bc 100644
--- a/src/Crawler/Profile.php
+++ b/src/Crawler/Profile.php
@@ -5,7 +5,7 @@
 use Spatie\Crawler\CrawlProfile;
 use Psr\Http\Message\UriInterface;
 
-class Profile implements CrawlProfile
+class Profile extends CrawlProfile
 {
     /** @var callable */
     protected $profile;
diff --git a/tests/CustomCrawlProfile.php b/tests/CustomCrawlProfile.php
index fe659ef..333399b 100644
--- a/tests/CustomCrawlProfile.php
+++ b/tests/CustomCrawlProfile.php
@@ -5,7 +5,7 @@
 use Spatie\Crawler\CrawlProfile;
 use Psr\Http\Message\UriInterface;
 
-class CustomCrawlProfile implements CrawlProfile
+class CustomCrawlProfile extends CrawlProfile
 {
     /**
      * Determine if the given url should be crawled.