diff --git a/composer.json b/composer.json
index 2beeeb68..4bd7ae40 100644
--- a/composer.json
+++ b/composer.json
@@ -40,7 +40,7 @@
         "swiftmailer/swiftmailer": "^6.2",
         "symfony/http-foundation": "^4.3",
         "symfony/psr-http-message-bridge": "^1.2",
-        "twig/twig": "^2.11",
+        "twig/twig": "^3.0",
         "vlucas/phpdotenv": "^3.3"
     },
     "require-dev": {
diff --git a/src/Controllers/Metrics/MetricsEngine.php b/src/Controllers/Metrics/MetricsEngine.php
index 8301e388..375bb096 100644
--- a/src/Controllers/Metrics/MetricsEngine.php
+++ b/src/Controllers/Metrics/MetricsEngine.php
@@ -142,7 +142,7 @@ class MetricsEngine implements EngineInterface
      * @param string|mixed[] $key
      * @param mixed          $value
      */
-    public function share($key, $value = null)
+    public function share($key, $value = null): void
     {
     }
 }
diff --git a/src/Renderer/Engine.php b/src/Renderer/Engine.php
index 60f1d686..e2ff23f2 100644
--- a/src/Renderer/Engine.php
+++ b/src/Renderer/Engine.php
@@ -11,7 +11,7 @@ abstract class Engine implements EngineInterface
      * @param mixed[]|string $key
      * @param null           $value
      */
-    public function share($key, $value = null)
+    public function share($key, $value = null): void
     {
         if (!is_array($key)) {
             $key = [$key => $value];
diff --git a/src/Renderer/EngineInterface.php b/src/Renderer/EngineInterface.php
index 3bce9c02..dd713029 100644
--- a/src/Renderer/EngineInterface.php
+++ b/src/Renderer/EngineInterface.php
@@ -23,5 +23,5 @@ interface EngineInterface
      * @param string|mixed[] $key
      * @param mixed          $value
      */
-    public function share($key, $value = null);
+    public function share($key, $value = null): void;
 }
diff --git a/src/Renderer/Renderer.php b/src/Renderer/Renderer.php
index de31ca74..ccda6881 100644
--- a/src/Renderer/Renderer.php
+++ b/src/Renderer/Renderer.php
@@ -18,7 +18,7 @@ class Renderer
      * @param mixed[] $data
      * @return string
      */
-    public function render($template, $data = [])
+    public function render(string $template, array $data = []): string
     {
         foreach ($this->renderer as $renderer) {
             if (!$renderer->canRender($template)) {
@@ -40,7 +40,7 @@ class Renderer
      *
      * @param EngineInterface $renderer
      */
-    public function addRenderer(EngineInterface $renderer)
+    public function addRenderer(EngineInterface $renderer): void
     {
         $this->renderer[] = $renderer;
     }
diff --git a/src/Renderer/Twig/Extensions/Assets.php b/src/Renderer/Twig/Extensions/Assets.php
index b77e4755..04d6c9c8 100644
--- a/src/Renderer/Twig/Extensions/Assets.php
+++ b/src/Renderer/Twig/Extensions/Assets.php
@@ -22,7 +22,7 @@ class Assets extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('asset', [$this, 'getAsset']),
@@ -31,9 +31,9 @@ class Assets extends TwigExtension
 
     /**
      * @param string $path
-     * @return UrlGenerator|string
+     * @return string
      */
-    public function getAsset($path)
+    public function getAsset(string $path): string
     {
         $path = ltrim($path, '/');
 
diff --git a/src/Renderer/Twig/Extensions/Authentication.php b/src/Renderer/Twig/Extensions/Authentication.php
index 33268ee6..061a9018 100644
--- a/src/Renderer/Twig/Extensions/Authentication.php
+++ b/src/Renderer/Twig/Extensions/Authentication.php
@@ -22,7 +22,7 @@ class Authentication extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('is_user', [$this, 'isAuthenticated']),
@@ -34,7 +34,7 @@ class Authentication extends TwigExtension
     /**
      * @return bool
      */
-    public function isAuthenticated()
+    public function isAuthenticated(): bool
     {
         return (bool)$this->auth->user();
     }
@@ -42,7 +42,7 @@ class Authentication extends TwigExtension
     /**
      * @return bool
      */
-    public function isGuest()
+    public function isGuest(): bool
     {
         return !$this->isAuthenticated();
     }
diff --git a/src/Renderer/Twig/Extensions/Config.php b/src/Renderer/Twig/Extensions/Config.php
index a82d2f73..da106957 100644
--- a/src/Renderer/Twig/Extensions/Config.php
+++ b/src/Renderer/Twig/Extensions/Config.php
@@ -22,7 +22,7 @@ class Config extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('config', [$this->config, 'get']),
diff --git a/src/Renderer/Twig/Extensions/Csrf.php b/src/Renderer/Twig/Extensions/Csrf.php
index 6e326824..fee1c1f9 100644
--- a/src/Renderer/Twig/Extensions/Csrf.php
+++ b/src/Renderer/Twig/Extensions/Csrf.php
@@ -22,7 +22,7 @@ class Csrf extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('csrf', [$this, 'getCsrfField'], ['is_safe' => ['html']]),
@@ -33,7 +33,7 @@ class Csrf extends TwigExtension
     /**
      * @return string
      */
-    public function getCsrfField()
+    public function getCsrfField(): string
     {
         return sprintf('<input type="hidden" name="_token" value="%s">', $this->getCsrfToken());
     }
@@ -41,7 +41,7 @@ class Csrf extends TwigExtension
     /**
      * @return string
      */
-    public function getCsrfToken()
+    public function getCsrfToken(): string
     {
         return $this->session->get('_token');
     }
diff --git a/src/Renderer/Twig/Extensions/Globals.php b/src/Renderer/Twig/Extensions/Globals.php
index a7914623..a809682c 100644
--- a/src/Renderer/Twig/Extensions/Globals.php
+++ b/src/Renderer/Twig/Extensions/Globals.php
@@ -24,7 +24,7 @@ class Globals extends TwigExtension implements GlobalsInterface
      *
      * @return array An array of global variables
      */
-    public function getGlobals()
+    public function getGlobals(): array
     {
         $user = $this->auth->user();
 
diff --git a/src/Renderer/Twig/Extensions/Legacy.php b/src/Renderer/Twig/Extensions/Legacy.php
index 41b00468..dc0c4775 100644
--- a/src/Renderer/Twig/Extensions/Legacy.php
+++ b/src/Renderer/Twig/Extensions/Legacy.php
@@ -22,7 +22,7 @@ class Legacy extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         $isSafeHtml = ['is_safe' => ['html']];
         return [
@@ -39,7 +39,7 @@ class Legacy extends TwigExtension
     /**
      * @return string
      */
-    public function getPage()
+    public function getPage(): string
     {
         if ($this->request->has('p')) {
             return $this->request->get('p');
diff --git a/src/Renderer/Twig/Extensions/Markdown.php b/src/Renderer/Twig/Extensions/Markdown.php
index 3d523f57..c23a0031 100644
--- a/src/Renderer/Twig/Extensions/Markdown.php
+++ b/src/Renderer/Twig/Extensions/Markdown.php
@@ -36,7 +36,7 @@ class Markdown extends TwigExtension
      * @param string $text
      * @return string
      */
-    public function render($text): string
+    public function render(string $text): string
     {
         return $this->renderer->text(htmlspecialchars($text));
     }
diff --git a/src/Renderer/Twig/Extensions/Session.php b/src/Renderer/Twig/Extensions/Session.php
index 378e977e..77b5b55a 100644
--- a/src/Renderer/Twig/Extensions/Session.php
+++ b/src/Renderer/Twig/Extensions/Session.php
@@ -22,7 +22,7 @@ class Session extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('session_get', [$this->session, 'get']),
diff --git a/src/Renderer/Twig/Extensions/Translation.php b/src/Renderer/Twig/Extensions/Translation.php
index 63b6fa5e..fff3bfa9 100644
--- a/src/Renderer/Twig/Extensions/Translation.php
+++ b/src/Renderer/Twig/Extensions/Translation.php
@@ -23,7 +23,7 @@ class Translation extends TwigExtension
     /**
      * @return array
      */
-    public function getFilters()
+    public function getFilters(): array
     {
         return [
             new TwigFilter('trans', [$this->translator, 'translate']),
@@ -33,7 +33,7 @@ class Translation extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('__', [$this->translator, 'translate']),
diff --git a/src/Renderer/Twig/Extensions/Url.php b/src/Renderer/Twig/Extensions/Url.php
index 84c6aa4d..17fd6ff0 100644
--- a/src/Renderer/Twig/Extensions/Url.php
+++ b/src/Renderer/Twig/Extensions/Url.php
@@ -22,7 +22,7 @@ class Url extends TwigExtension
     /**
      * @return TwigFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('url', [$this, 'getUrl']),
@@ -32,9 +32,9 @@ class Url extends TwigExtension
     /**
      * @param string $path
      * @param array  $parameters
-     * @return UrlGenerator|string
+     * @return string
      */
-    public function getUrl($path, $parameters = [])
+    public function getUrl(string $path, array $parameters = []): string
     {
         $path = str_replace('_', '-', $path);
 
diff --git a/src/Renderer/TwigLoader.php b/src/Renderer/TwigLoader.php
index 3c4c8ab8..1bcbbd71 100644
--- a/src/Renderer/TwigLoader.php
+++ b/src/Renderer/TwigLoader.php
@@ -10,10 +10,10 @@ class TwigLoader extends FilesystemLoader
     /**
      * @param string $name
      * @param bool   $throw
-     * @return string|false|null
+     * @return string|null
      * @throws ErrorLoader
      */
-    public function findTemplate($name, $throw = true)
+    public function findTemplate(string $name, bool $throw = true): ?string
     {
         $extension = '.twig';
         $extensionLength = mb_strlen($extension);
diff --git a/src/Renderer/TwigServiceProvider.php b/src/Renderer/TwigServiceProvider.php
index 3a365a5e..d4e4a939 100644
--- a/src/Renderer/TwigServiceProvider.php
+++ b/src/Renderer/TwigServiceProvider.php
@@ -95,7 +95,7 @@ class TwigServiceProvider extends ServiceProvider
      * @param string $class
      * @param string $alias
      */
-    protected function registerTwigExtensions($class, $alias)
+    protected function registerTwigExtensions(string $class, string $alias)
     {
         $alias = 'twig.extension.' . $alias;
 
diff --git a/tests/Unit/Renderer/TwigServiceProviderTest.php b/tests/Unit/Renderer/TwigServiceProviderTest.php
index 7696d28f..3336e015 100644
--- a/tests/Unit/Renderer/TwigServiceProviderTest.php
+++ b/tests/Unit/Renderer/TwigServiceProviderTest.php
@@ -12,6 +12,7 @@ use ReflectionClass as Reflection;
 use ReflectionException;
 use stdClass;
 use Twig\Environment as Twig;
+use Twig\Extension\AbstractExtension;
 use Twig\Extension\CoreExtension as TwigCore;
 use Twig\Extension\ExtensionInterface as ExtensionInterface;
 use Twig\Loader\LoaderInterface as TwigLoaderInterface;
@@ -103,9 +104,15 @@ class TwigServiceProviderTest extends ServiceProviderTest
         /** @var Config|MockObject $config */
         $config = $this->createMock(Config::class);
         /** @var TwigCore|MockObject $twigCore */
-        $twigCore = $this->getMockBuilder(stdClass::class)
-            ->addMethods(['setTimezone'])
-            ->getMock();
+        $twigCore = $this->getMockForAbstractClass(
+            AbstractExtension::class,
+            [],
+            '',
+            true,
+            true,
+            true,
+            ['setTimezone']
+        );
 
         $app = $this->getApp(['make', 'instance', 'tag', 'get']);