diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 99ed9722a..4e89a9421 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -11,22 +11,26 @@ on:
 
 jobs:
     tests:
-        runs-on: ubuntu-latest
+        runs-on: ubuntu-18.04
 
-        name: "PHP ${{ matrix.php }}, MySQL ${{ matrix.mysql }}, Sylius ${{ matrix.sylius }}"
+        name: "Sylius ${{ matrix.sylius }}, PHP ${{ matrix.php }}, Symfony ${{ matrix.symfony }}, MySQL ${{ matrix.mysql }}"
 
         strategy:
             fail-fast: false
             matrix:
                 php: [7.4, 7.3]
+                symfony: [^4.4, ^5.2]
+                sylius: [~1.8.0, ~1.9.0@beta]
                 node: [10.x]
                 mysql: [5.7, 8.0]
-                sylius: [1.8.*]
 
                 exclude:
                     -
                         php: 7.3
                         mysql: 8.0
+                    -
+                        sylius: ~1.8.0
+                        symfony: ^5.2
 
         env:
             APP_ENV: test
@@ -101,6 +105,18 @@ jobs:
                 run: |
                     composer require "sylius/sylius:${{ matrix.sylius }}" --no-update
 
+            -
+                name: Restrict Symfony version
+                if: matrix.symfony != ''
+                run: |
+                    composer global require --no-progress --no-scripts --no-plugins "symfony/flex:^1.10"
+                    composer config extra.symfony.require "${{ matrix.symfony }}"
+
+            -
+                name: Restrict Sylius version
+                if: matrix.sylius != ''
+                run: composer require "sylius/sylius:${{ matrix.sylius }}" --no-update --no-scripts --no-interaction
+
             -
                 name: Install PHP dependencies
                 run: composer update --no-interaction
diff --git a/composer.json b/composer.json
index 62f1d58ce..d0f848a9e 100644
--- a/composer.json
+++ b/composer.json
@@ -23,33 +23,33 @@
         "knplabs/knp-snappy-bundle": "^1.7",
         "myclabs/php-enum": "^1.7",
         "sylius/resource-bundle": "^1.6",
-        "sylius/sylius": "^1.8",
-        "symfony/messenger": "^4.4"
+        "sylius/sylius": "~1.8.0 || ~1.9.0@beta",
+        "symfony/messenger": "^4.4 || ^5.2"
     },
     "require-dev": {
         "behat/behat": "^3.6",
-        "behat/mink": "^1.8",
-        "behat/mink-browserkit-driver": "^1.3",
-        "behat/mink-extension": "^2.3",
         "behat/mink-selenium2-driver": "^1.4",
         "dmore/behat-chrome-extension": "^1.3",
         "dmore/chrome-mink-driver": "^2.7",
+        "friends-of-behat/mink": "^1.8",
+        "friends-of-behat/mink-browserkit-driver": "^1.3",
+        "friends-of-behat/mink-extension": "^2.3",
         "friends-of-behat/page-object-extension": "^0.3",
         "friends-of-behat/suite-settings-extension": "^1.0",
         "friends-of-behat/symfony-extension": "^2.1",
         "friends-of-behat/variadic-extension": "^1.3",
+        "friendsofsymfony/oauth-server-bundle": "^1.6 || >2.0.0-alpha.0 ^2.0@dev",
         "lakion/mink-debug-extension": "^1.2.3",
         "phpspec/phpspec": "^6.0",
         "phpstan/phpstan": "0.12.29",
         "phpstan/phpstan-webmozart-assert": "0.12.6",
         "phpunit/phpunit": "^8.5",
         "sylius-labs/coding-standard": "^3.2",
-        "symfony/browser-kit": "^4.4",
-        "symfony/debug-bundle": "^4.4",
-        "symfony/dotenv": "^4.4",
-        "symfony/intl": "^4.4",
-        "symfony/web-profiler-bundle": "^4.4",
-        "symfony/web-server-bundle": "^4.4"
+        "symfony/browser-kit": "^4.4 || ^5.2",
+        "symfony/debug-bundle": "^4.4 || ^5.2",
+        "symfony/dotenv": "^4.4 || ^5.2",
+        "symfony/intl": "^4.4 || ^5.2",
+        "symfony/web-profiler-bundle": "^4.4 || ^5.2"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 71079858e..c0456fcb5 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -14,8 +14,8 @@ final class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder(): TreeBuilder
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('sylius_refund_plugin');
+        $treeBuilder = new TreeBuilder('sylius_refund_plugin');
+        $rootNode = $treeBuilder->getRootNode();
 
         return $treeBuilder;
     }
diff --git a/src/Resources/config/services/generator.xml b/src/Resources/config/services/generator.xml
index 5721b83b8..92a33ff5e 100644
--- a/src/Resources/config/services/generator.xml
+++ b/src/Resources/config/services/generator.xml
@@ -22,7 +22,7 @@
 
         <service id="Sylius\RefundPlugin\Generator\CreditMemoPdfFileGenerator">
             <argument type="service" id="sylius_refund.repository.credit_memo" />
-            <argument type="service" id="templating.engine.twig" />
+            <argument type="service" id="twig" />
             <argument type="service" id="knp_snappy.pdf" />
             <argument type="service" id="file_locator" />
             <argument>@SyliusRefundPlugin/Download/creditMemo.html.twig</argument>
diff --git a/tests/Application/Kernel.php b/tests/Application/Kernel.php
index 0da88b306..6038b297d 100644
--- a/tests/Application/Kernel.php
+++ b/tests/Application/Kernel.php
@@ -6,11 +6,13 @@
 
 use ProxyManager\Proxy\VirtualProxyInterface;
 use PSS\SymfonyMockerContainer\DependencyInjection\MockerContainer;
+use Sylius\Bundle\CoreBundle\Application\Kernel as SyliusKernel;
 use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
 use Symfony\Component\Config\Loader\LoaderInterface;
 use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpKernel\Bundle\BundleInterface;
 use Symfony\Component\HttpKernel\Kernel as BaseKernel;
 use Symfony\Component\Routing\RouteCollectionBuilder;
 
@@ -39,33 +41,29 @@ public function getLogDir(): string
 
     public function registerBundles(): iterable
     {
-        $contents = require $this->getProjectDir() . '/config/bundles.php';
-        foreach ($contents as $class => $envs) {
-            if (isset($envs['all']) || isset($envs[$this->environment])) {
-                yield new $class();
-            }
+        foreach ($this->getConfigurationDirectories() as $confDir) {
+            yield from $this->registerBundlesFromFile($confDir . '/bundles.php');
         }
     }
 
     protected function configureContainer(ContainerBuilder $container, LoaderInterface $loader): void
     {
-        $container->addResource(new FileResource($this->getProjectDir() . '/config/bundles.php'));
+        foreach ($this->getConfigurationDirectories() as $confDir) {
+            $container->addResource(new FileResource($confDir . '/bundles.php'));
+        }
+
         $container->setParameter('container.dumper.inline_class_loader', true);
-        $confDir = $this->getProjectDir() . '/config';
 
-        $loader->load($confDir . '/{packages}/*' . self::CONFIG_EXTS, 'glob');
-        $loader->load($confDir . '/{packages}/' . $this->environment . '/**/*' . self::CONFIG_EXTS, 'glob');
-        $loader->load($confDir . '/{services}' . self::CONFIG_EXTS, 'glob');
-        $loader->load($confDir . '/{services}_' . $this->environment . self::CONFIG_EXTS, 'glob');
+        foreach ($this->getConfigurationDirectories() as $confDir) {
+            $this->loadContainerConfiguration($loader, $confDir);
+        }
     }
 
     protected function configureRoutes(RouteCollectionBuilder $routes): void
     {
-        $confDir = $this->getProjectDir() . '/config';
-
-        $routes->import($confDir . '/{routes}/*' . self::CONFIG_EXTS, '/', 'glob');
-        $routes->import($confDir . '/{routes}/' . $this->environment . '/**/*' . self::CONFIG_EXTS, '/', 'glob');
-        $routes->import($confDir . '/{routes}' . self::CONFIG_EXTS, '/', 'glob');
+        foreach ($this->getConfigurationDirectories() as $confDir) {
+            $this->loadRoutesConfiguration($routes, $confDir);
+        }
     }
 
     protected function getContainerBaseClass(): string
@@ -81,4 +79,41 @@ private function isTestEnvironment(): bool
     {
         return 0 === strpos($this->getEnvironment(), 'test');
     }
+
+    private function loadContainerConfiguration(LoaderInterface $loader, string $confDir): void
+    {
+        $loader->load($confDir . '/{packages}/*' . self::CONFIG_EXTS, 'glob');
+        $loader->load($confDir . '/{packages}/' . $this->environment . '/**/*' . self::CONFIG_EXTS, 'glob');
+        $loader->load($confDir . '/{services}' . self::CONFIG_EXTS, 'glob');
+        $loader->load($confDir . '/{services}_' . $this->environment . self::CONFIG_EXTS, 'glob');
+    }
+
+    private function loadRoutesConfiguration(RouteCollectionBuilder $routes, string $confDir): void
+    {
+        $routes->import($confDir . '/{routes}/*' . self::CONFIG_EXTS, '/', 'glob');
+        $routes->import($confDir . '/{routes}/' . $this->environment . '/**/*' . self::CONFIG_EXTS, '/', 'glob');
+        $routes->import($confDir . '/{routes}' . self::CONFIG_EXTS, '/', 'glob');
+    }
+
+    /**
+     * @return BundleInterface[]
+     */
+    private function registerBundlesFromFile(string $bundlesFile): iterable
+    {
+        $contents = require $bundlesFile;
+        foreach ($contents as $class => $envs) {
+            if (isset($envs['all']) || isset($envs[$this->environment])) {
+                yield new $class();
+            }
+        }
+    }
+
+    /**
+     * @return string[]
+     */
+    private function getConfigurationDirectories(): iterable
+    {
+        yield $this->getProjectDir() . '/config';
+        yield $this->getProjectDir() . '/config/sylius/' . SyliusKernel::MAJOR_VERSION . '.' . SyliusKernel::MINOR_VERSION;
+    }
 }
diff --git a/tests/Application/config/bundles.php b/tests/Application/config/bundles.php
index 2ac911a99..9d9790ccd 100644
--- a/tests/Application/config/bundles.php
+++ b/tests/Application/config/bundles.php
@@ -7,7 +7,6 @@
     Symfony\Bundle\SwiftmailerBundle\SwiftmailerBundle::class => ['all' => true],
     Symfony\Bundle\TwigBundle\TwigBundle::class => ['all' => true],
     Doctrine\Bundle\DoctrineBundle\DoctrineBundle::class => ['all' => true],
-    Doctrine\Bundle\DoctrineCacheBundle\DoctrineCacheBundle::class => ['all' => true],
     Sylius\Bundle\OrderBundle\SyliusOrderBundle::class => ['all' => true],
     Sylius\Bundle\MoneyBundle\SyliusMoneyBundle::class => ['all' => true],
     Sylius\Bundle\CurrencyBundle\SyliusCurrencyBundle::class => ['all' => true],
@@ -40,12 +39,10 @@
     Liip\ImagineBundle\LiipImagineBundle::class => ['all' => true],
     Payum\Bundle\PayumBundle\PayumBundle::class => ['all' => true],
     Stof\DoctrineExtensionsBundle\StofDoctrineExtensionsBundle::class => ['all' => true],
-    WhiteOctober\PagerfantaBundle\WhiteOctoberPagerfantaBundle::class => ['all' => true],
     Doctrine\Bundle\MigrationsBundle\DoctrineMigrationsBundle::class => ['all' => true],
     Sylius\Bundle\FixturesBundle\SyliusFixturesBundle::class => ['all' => true],
     Sylius\Bundle\PayumBundle\SyliusPayumBundle::class => ['all' => true],
     Sylius\Bundle\ThemeBundle\SyliusThemeBundle::class => ['all' => true],
-    Symfony\Bundle\WebServerBundle\WebServerBundle::class => ['all' => true],
     Sylius\Bundle\AdminBundle\SyliusAdminBundle::class => ['all' => true],
     Sylius\Bundle\ShopBundle\SyliusShopBundle::class => ['all' => true],
     FOS\OAuthServerBundle\FOSOAuthServerBundle::class => ['all' => true],
diff --git a/tests/Application/config/packages/_sylius.yaml b/tests/Application/config/packages/_sylius.yaml
index 8ad31ca4a..aa0c8387c 100644
--- a/tests/Application/config/packages/_sylius.yaml
+++ b/tests/Application/config/packages/_sylius.yaml
@@ -6,6 +6,8 @@ imports:
 
     - { resource: "@SyliusShopBundle/Resources/config/app/config.yml" }
 
+    - { resource: "@SyliusApiBundle/Resources/config/app/config.yaml" }
+
 parameters:
     sylius_core.public_dir: '%kernel.project_dir%/public'
 
diff --git a/tests/Application/config/packages/framework.yaml b/tests/Application/config/packages/framework.yaml
index e74ed811e..9b445011c 100644
--- a/tests/Application/config/packages/framework.yaml
+++ b/tests/Application/config/packages/framework.yaml
@@ -2,6 +2,5 @@ framework:
     secret: '%env(APP_SECRET)%'
     form: true
     csrf_protection: true
-    templating: { engines: ["twig"] }
     session:
         handler_id: ~
diff --git a/tests/Application/config/sylius/1.8/bundles.php b/tests/Application/config/sylius/1.8/bundles.php
new file mode 100644
index 000000000..74ee2bc02
--- /dev/null
+++ b/tests/Application/config/sylius/1.8/bundles.php
@@ -0,0 +1,6 @@
+<?php
+
+return [
+    Doctrine\Bundle\DoctrineCacheBundle\DoctrineCacheBundle::class => ['all' => true],
+    WhiteOctober\PagerfantaBundle\WhiteOctoberPagerfantaBundle::class => ['all' => true],
+];
diff --git a/tests/Application/config/packages/dev/jms_serializer.yaml b/tests/Application/config/sylius/1.8/packages/dev/jms_serializer.yaml
similarity index 100%
rename from tests/Application/config/packages/dev/jms_serializer.yaml
rename to tests/Application/config/sylius/1.8/packages/dev/jms_serializer.yaml
diff --git a/tests/Application/config/sylius/1.8/packages/framework.yaml b/tests/Application/config/sylius/1.8/packages/framework.yaml
new file mode 100644
index 000000000..62f82d357
--- /dev/null
+++ b/tests/Application/config/sylius/1.8/packages/framework.yaml
@@ -0,0 +1,2 @@
+framework:
+    templating: { engines: ["twig"] }
diff --git a/tests/Application/config/packages/jms_serializer.yaml b/tests/Application/config/sylius/1.8/packages/jms_serializer.yaml
similarity index 100%
rename from tests/Application/config/packages/jms_serializer.yaml
rename to tests/Application/config/sylius/1.8/packages/jms_serializer.yaml
diff --git a/tests/Application/config/packages/prod/jms_serializer.yaml b/tests/Application/config/sylius/1.8/packages/prod/jms_serializer.yaml
similarity index 100%
rename from tests/Application/config/packages/prod/jms_serializer.yaml
rename to tests/Application/config/sylius/1.8/packages/prod/jms_serializer.yaml
diff --git a/tests/Application/config/routes/dev/twig.yaml b/tests/Application/config/sylius/1.8/routes/dev/twig.yaml
similarity index 100%
rename from tests/Application/config/routes/dev/twig.yaml
rename to tests/Application/config/sylius/1.8/routes/dev/twig.yaml
diff --git a/tests/Application/config/sylius/1.9/bundles.php b/tests/Application/config/sylius/1.9/bundles.php
new file mode 100644
index 000000000..bd33f4ae8
--- /dev/null
+++ b/tests/Application/config/sylius/1.9/bundles.php
@@ -0,0 +1,6 @@
+<?php
+
+return [
+    BabDev\PagerfantaBundle\BabDevPagerfantaBundle::class => ['all' => true],
+    SyliusLabs\Polyfill\Symfony\Security\Bundle\SyliusLabsPolyfillSymfonySecurityBundle::class => ['all' => true],
+];
diff --git a/tests/Application/config/sylius/1.9/packages/dev/jms_serializer.yaml b/tests/Application/config/sylius/1.9/packages/dev/jms_serializer.yaml
new file mode 100644
index 000000000..2f32a9b18
--- /dev/null
+++ b/tests/Application/config/sylius/1.9/packages/dev/jms_serializer.yaml
@@ -0,0 +1,12 @@
+jms_serializer:
+    visitors:
+        json_serialization:
+            options:
+                - JSON_PRETTY_PRINT
+                - JSON_UNESCAPED_SLASHES
+                - JSON_PRESERVE_ZERO_FRACTION
+        json_deserialization:
+            options:
+                - JSON_PRETTY_PRINT
+                - JSON_UNESCAPED_SLASHES
+                - JSON_PRESERVE_ZERO_FRACTION
diff --git a/tests/Application/config/sylius/1.9/packages/jms_serializer.yaml b/tests/Application/config/sylius/1.9/packages/jms_serializer.yaml
new file mode 100644
index 000000000..ed7bc613f
--- /dev/null
+++ b/tests/Application/config/sylius/1.9/packages/jms_serializer.yaml
@@ -0,0 +1,4 @@
+jms_serializer:
+    visitors:
+        xml_serialization:
+            format_output: '%kernel.debug%'
diff --git a/tests/Application/config/sylius/1.9/packages/prod/jms_serializer.yaml b/tests/Application/config/sylius/1.9/packages/prod/jms_serializer.yaml
new file mode 100644
index 000000000..c2881820f
--- /dev/null
+++ b/tests/Application/config/sylius/1.9/packages/prod/jms_serializer.yaml
@@ -0,0 +1,10 @@
+jms_serializer:
+    visitors:
+        json_serialization:
+            options:
+                - JSON_UNESCAPED_SLASHES
+                - JSON_PRESERVE_ZERO_FRACTION
+        json_deserialization:
+            options:
+                - JSON_UNESCAPED_SLASHES
+                - JSON_PRESERVE_ZERO_FRACTION
diff --git a/tests/Application/public/index.php b/tests/Application/public/index.php
index b35db6266..7840b1527 100644
--- a/tests/Application/public/index.php
+++ b/tests/Application/public/index.php
@@ -1,10 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 use Tests\Sylius\RefundPlugin\Application\Kernel;
-use Symfony\Component\Debug\Debug;
+use Symfony\Component\ErrorHandler\Debug;
 use Symfony\Component\HttpFoundation\Request;
 
-require dirname(__DIR__).'/config/bootstrap.php';
+require dirname(__DIR__) . '/config/bootstrap.php';
 
 if ($_SERVER['APP_DEBUG']) {
     umask(0000);