diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index d2885e4..61be99f 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [7.3, 7.4]
+        php: [7.3, 7.4, 8.0]
         dependency-version: [prefer-lowest, prefer-stable]
 
     name: PHP ${{ matrix.php }} - ${{ matrix.dependency-version }}
@@ -30,9 +30,10 @@ jobs:
           php-version: ${{ matrix.php }}
           extensions: curl, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, iconv, intl
           coverage: xdebug
+          tools: composer:v2
 
       - name: Install dependencies
-        run: composer update --${{ matrix.dependency-version }} --prefer-dist --no-interaction --no-suggest
+        run: composer update --${{ matrix.dependency-version }} --prefer-dist --no-interaction
 
       - name: Execute tests
         run: |
diff --git a/.scrutinizer.yml b/.scrutinizer.yml
index 69d4755..8a9285f 100644
--- a/.scrutinizer.yml
+++ b/.scrutinizer.yml
@@ -22,7 +22,7 @@ checks:
 tools:
     external_code_coverage:
         timeout: 600
-        runs: 4
+        runs: 6
     php_code_sniffer:
         enabled: true
         config:
diff --git a/composer.json b/composer.json
index e16ad06..fcb0732 100644
--- a/composer.json
+++ b/composer.json
@@ -14,15 +14,15 @@
     "type":    "library",
     "license": "MIT",
     "require": {
-        "php": "^7.3",
+        "php": "^7.3|^8.0",
         "ext-json": "*",
         "arcanedev/support": "^8.0"
     },
     "require-dev": {
         "ext-intl": "*",
-        "orchestra/testbench": "^6.0",
-        "mockery/mockery": "^1.3.1",
-        "phpunit/phpunit": "^9.3"
+        "mockery/mockery": "^1.4.2",
+        "orchestra/testbench": "^6.4",
+        "phpunit/phpunit": "^9.3.3"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Utilities/Url.php b/src/Utilities/Url.php
index 5a88401..c1923cd 100644
--- a/src/Utilities/Url.php
+++ b/src/Utilities/Url.php
@@ -55,7 +55,7 @@ public static function substituteAttributes(array $attributes, $uri)
             if ($value instanceof RouteBindable)
                 $value = $value->getWildcardValue();
 
-            $uri = str_replace(['{'.$key.'?}', '{'.$key.'}'], $value, $uri);
+            $uri = str_replace(['{'.$key.'?}', '{'.$key.'}'], (string) $value, $uri);
         }
 
         // delete empty optional arguments that are not in the $attributes array