diff --git a/.gitattributes b/.gitattributes
index c47225a..ad4bcf8 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,3 +1,7 @@
+# Define the line ending behavior of the different file extensions
+# Set default behavior, in case users don't have core.autocrlf set.
+* text text=auto eol=lf
+
 .editorconfig     export-ignore
 .gitattributes    export-ignore
 /.github/         export-ignore
diff --git a/.gitignore b/.gitignore
index 16b4a20..f10df12 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,8 @@
-/behat.yml
-/build/
-/composer.lock
-/phpspec.yml
-/phpunit.xml
-/vendor/
+behat.yml
+build/
+composer.lock
+phpspec.yml
+phpunit.xml
+.phpunit.result.cache
+vendor/
+.idea/
diff --git a/.travis.yml b/.travis.yml
index befd55b..92ef314 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,15 +1,8 @@
 language: php
 
-sudo: false
-
-cache:
-    directories:
-        - $HOME/.composer/cache/files
-
 php:
-    - 5.6
-    - 7.0
-    - 7.1
+    - 7.2
+    - 7.4
 
 env:
     global:
@@ -25,7 +18,7 @@ matrix:
           dist: trusty
     fast_finish: true
     include:
-        - php: 5.6
+        - php: 7.2
           env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" COVERAGE=true TEST_COMMAND="composer test-ci"
         - php: hhvm
           dist: trusty
@@ -47,3 +40,7 @@ script:
 after_success:
     - if [[ $COVERAGE = true ]]; then wget https://scrutinizer-ci.com/ocular.phar; fi
     - if [[ $COVERAGE = true ]]; then php ocular.phar code-coverage:upload --format=php-clover build/coverage.xml; fi
+
+cache:
+    directories:
+        - $HOME/.composer/cache/files
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a367104..0f6361c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change Log
 
+## 0.3.0
+
+- CakePHP 4.x compatibility
+
 ## 0.2.0
 
 ### Changed
diff --git a/README.md b/README.md
index 59ca624..6840dc0 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,9 @@
 [![Quality Score](https://img.shields.io/scrutinizer/g/php-http/cakephp-adapter.svg?style=flat-square)](https://scrutinizer-ci.com/g/php-http/cakephp-adapter)
 [![Total Downloads](https://img.shields.io/packagist/dt/php-http/cakephp-adapter.svg?style=flat-square)](https://packagist.org/packages/php-http/cakephp-adapter)
 
-**Httplug adapter for the cakephp network library**
+Httplug adapter for the **CakePHP** HTTP library.
 
+This branch is for use with CakePHP 4.0+.
 
 ## Install
 
diff --git a/composer.json b/composer.json
index eaa0b43..01022e5 100644
--- a/composer.json
+++ b/composer.json
@@ -11,13 +11,14 @@
         }
     ],
     "require": {
-        "php": "^5.6 || ^7.0",
-        "php-http/httplug": "^1.0",
+        "php": "^7.2",
+        "php-http/httplug": "^2.0",
         "php-http/discovery": "^1.0",
-        "cakephp/cakephp": "^3.4.12"
+        "cakephp/cakephp": "^4.0"
     },
     "require-dev": {
-        "php-http/client-integration-tests": "^0.6"
+        "php-http/client-integration-tests": "^0.6",
+        "phpunit/phpunit": "^8.5"
     },
     "autoload": {
         "psr-4": {
@@ -36,9 +37,10 @@
         "test": "vendor/bin/phpunit",
         "test-ci": "vendor/bin/phpunit --coverage-clover build/coverage.xml"
     },
+    "prefer-stable": true,
     "extra": {
         "branch-alias": {
-            "dev-master": "0.2-dev"
+            "dev-master": "0.3-dev"
         }
     }
 }
diff --git a/src/Client.php b/src/Client.php
index 613493c..dfd9e6b 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -10,21 +10,27 @@
 use Http\Discovery\MessageFactoryDiscovery;
 use Http\Message\ResponseFactory;
 use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use Throwable;
 
 /**
  * Client compatible with PSR7 and Httplug interfaces, using a CakePHP client.
  */
 class Client implements HttpClient
 {
-    /** @var CakeClient */
+    /**
+     * @var \Cake\Http\Client
+     */
     private $client;
 
-    /** @var ResponseFactory */
+    /**
+     * @var \Http\Message\ResponseFactory
+     */
     private $responseFactory;
 
     /**
-     * @param CakeClient      $client
-     * @param ResponseFactory $responseFactory
+     * @param \Cake\Http\Client|null $client
+     * @param \Http\Message\ResponseFactory|null $responseFactory
      */
     public function __construct(CakeClient $client = null, ResponseFactory $responseFactory = null)
     {
@@ -33,9 +39,9 @@ public function __construct(CakeClient $client = null, ResponseFactory $response
     }
 
     /**
-     * {@inheritdoc}
+     * @inheritdoc
      */
-    public function sendRequest(RequestInterface $request)
+    public function sendRequest(RequestInterface $request): ResponseInterface
     {
         $cakeRequest = new Request(
             (string) $request->getUri(),
@@ -47,13 +53,13 @@ public function sendRequest(RequestInterface $request)
             ->withProtocolVersion($request->getProtocolVersion())
             ->withBody($request->getBody());
 
-        if (null === $cakeRequest->header('Content-Type')) {
-            $cakeRequest->header('Content-Type', 'application/x-www-form-urlencoded');
+        if (null === $cakeRequest->getHeader('Content-Type')) {
+            $cakeRequest = $cakeRequest->withHeader('Content-Type', 'application/x-www-form-urlencoded');
         }
 
         try {
-            $response = $this->client->send($cakeRequest, $this->client->config());
-        } catch (Exception $exception) {
+            $response = $this->client->send($cakeRequest, $this->client->getConfig());
+        } catch (Throwable $exception) {
             throw new NetworkException('Failed to send request', $request, $exception);
         }
 
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index bb598ad..5b7b2b8 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -7,7 +7,10 @@
 
 class ClientTest extends HttpClientTest
 {
-    protected function createHttpAdapter()
+    /**
+     * @return \Http\Adapter\Cake\Client
+     */
+    protected function createHttpAdapter(): Client
     {
         return new Client();
     }