diff --git a/.travis.yml b/.travis.yml
index def9a8a..cfb5cea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,22 +2,24 @@ language: php
 
 php:
     - 7.1
-    - nightly
+    - 7.2
 
-matrix:
-    allow_failures:
-        - php: nightly
-    fast_finish: true
+env:
+    - SYMFONY_VERSION=3.3.*
+    - SYMFONY_VERSION=3.4.*
+    - SYMFONY_VERSION=4.0.*
 
 cache:
     directories:
-        - vendor
+        - ~/.composer/cache/files
 
 before_install:
     - phpenv config-rm xdebug.ini || true
 
 install:
-    - composer update --prefer-dist
+    - composer require symfony/dependency-injection:${SYMFONY_VERSION} --no-update --no-scripts --prefer-dist
+    - composer require --dev symfony/http-kernel:${SYMFONY_VERSION} --no-update --no-scripts --prefer-dist
+    - composer update --prefer-dist $PREFER_LOWEST
 
 script:
     - composer validate --strict
diff --git a/composer.json b/composer.json
index 792c7a9..3e7e3b5 100644
--- a/composer.json
+++ b/composer.json
@@ -13,16 +13,16 @@
         "php": "^7.1",
 
         "behat/behat": "^3.1",
-        "symfony/dependency-injection": "^2.8|^3.0"
+        "symfony/dependency-injection": "^3.3|^4.0"
     },
     "require-dev": {
         "friends-of-behat/test-context": "^1.0",
-        "phpspec/phpspec": "^4.0@alpha",
-        "symfony/http-kernel": "^2.8|^3.0",
-        "phpunit/phpunit": "^5.7.13|^6.0"
+        "phpspec/phpspec": "^4.0",
+        "symfony/http-kernel": "^3.3|^4.0",
+        "phpunit/phpunit": "^6.0"
     },
     "suggest": {
-        "symfony/http-kernel": "^2.8|^3.0"
+        "symfony/http-kernel": "^3.3|^4.0"
     },
     "autoload": {
         "psr-4": { "FriendsOfBehat\\CrossContainerExtension\\": "src/" }
diff --git a/spec/ContainerBasedContainerAccessorSpec.php b/spec/ContainerBasedContainerAccessorSpec.php
index bbe01b7..b20e684 100644
--- a/spec/ContainerBasedContainerAccessorSpec.php
+++ b/spec/ContainerBasedContainerAccessorSpec.php
@@ -41,7 +41,7 @@ function it_gets_a_service(Container $container): void
 
     function it_gets_parameters_from_frozen_container(Container $container): void
     {
-        $container->isFrozen()->willReturn(true);
+        $container->isCompiled()->willReturn(true);
         $container->getParameterBag()->willReturn(new ParameterBag(['name' => 'value']));
 
         $this->getParameters()->shouldReturn(['name' => 'value']);
@@ -49,7 +49,7 @@ function it_gets_parameters_from_frozen_container(Container $container): void
 
     function it_gets_parameters_from_not_frozen_container(Container $container): void
     {
-        $container->isFrozen()->willReturn(false);
+        $container->isCompiled()->willReturn(false);
         $container->getParameterBag()->willReturn(new ParameterBag(['name' => 'value']));
 
         $this->getParameters()->shouldReturn(['name' => 'value']);
diff --git a/spec/KernelBasedContainerAccessorSpec.php b/spec/KernelBasedContainerAccessorSpec.php
index 4ec5d94..31f5d41 100644
--- a/spec/KernelBasedContainerAccessorSpec.php
+++ b/spec/KernelBasedContainerAccessorSpec.php
@@ -53,7 +53,7 @@ function it_gets_parameters_from_frozen_container(KernelInterface $kernel, Conta
     {
         $kernel->getContainer()->willReturn($container);
 
-        $container->isFrozen()->willReturn(true);
+        $container->isCompiled()->willReturn(true);
         $container->getParameterBag()->willReturn(new ParameterBag(['name' => 'value']));
 
         $this->getParameters()->shouldReturn(['name' => 'value']);
@@ -63,7 +63,7 @@ function it_gets_parameters_from_not_frozen_container(KernelInterface $kernel, C
     {
         $kernel->getContainer()->willReturn($container);
 
-        $container->isFrozen()->willReturn(false);
+        $container->isCompiled()->willReturn(false);
         $container->getParameterBag()->willReturn(new ParameterBag(['name' => 'value']));
 
         $this->getParameters()->shouldReturn(['name' => 'value']);
diff --git a/src/ContainerBasedContainerAccessor.php b/src/ContainerBasedContainerAccessor.php
index 39c4590..8d69f89 100644
--- a/src/ContainerBasedContainerAccessor.php
+++ b/src/ContainerBasedContainerAccessor.php
@@ -45,7 +45,7 @@ public function getParameters(): array
     {
         $parameterBag = $this->container->getParameterBag();
 
-        if (!$this->container->isFrozen()) {
+        if (!$this->container->isCompiled()) {
             $parameterBag = clone $parameterBag;
             $parameterBag->resolve();
         }
diff --git a/tests/CrossContainerProcessorTest.php b/tests/CrossContainerProcessorTest.php
index 7feddb1..14b296e 100644
--- a/tests/CrossContainerProcessorTest.php
+++ b/tests/CrossContainerProcessorTest.php
@@ -29,12 +29,12 @@ final class CrossContainerProcessorTest extends TestCase
     public function it_resolves_cross_container_references_in_service_argument(): void
     {
         $externalContainer = new ContainerBuilder();
-        $externalContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [['foo' => 'bar']]));
+        $externalContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [['foo' => 'bar']]))->setPublic(true));
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [
+        $baseContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [
             new Reference('__external__.array_object'),
-        ]));
+        ]))->setPublic(true));
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);
 
@@ -48,12 +48,12 @@ public function it_resolves_cross_container_references_in_service_argument(): vo
     public function it_resolves_cross_container_references_in_service_argument_array(): void
     {
         $externalContainer = new ContainerBuilder();
-        $externalContainer->setDefinition('std_class', new Definition(\stdClass::class));
+        $externalContainer->setDefinition('std_class', (new Definition(\stdClass::class))->setPublic(true));
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [
+        $baseContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [
             ['std' => ['class' => new Reference('__external__.std_class')]],
-        ]));
+        ]))->setPublic(true));
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);
 
@@ -67,14 +67,14 @@ public function it_resolves_cross_container_references_in_service_argument_array
     public function it_resolves_cross_container_references_in_service_argument_anonymous_definition(): void
     {
         $externalContainer = new ContainerBuilder();
-        $externalContainer->setDefinition('std_class', new Definition(\stdClass::class));
+        $externalContainer->setDefinition('std_class', (new Definition(\stdClass::class))->setPublic(true));
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [
+        $baseContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [
             new Definition(\ArrayObject::class, [
                 ['std_class' => new Reference('__external__.std_class')],
             ]),
-        ]));
+        ]))->setPublic(true));
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);
 
@@ -88,11 +88,14 @@ public function it_resolves_cross_container_references_in_service_argument_anony
     public function it_resolves_cross_container_references_in_service_factory(): void
     {
         $externalContainer = new ContainerBuilder();
-        $externalContainer->setDefinition('array_object_factory', new Definition(\ArrayObject::class, [['old' => 'old']]));
+        $externalContainer->setDefinition('array_object_factory', (new Definition(\ArrayObject::class, [['old' => 'old']]))->setPublic(true));
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object',
-            (new Definition(\ArrayObject::class, [['new' => 'new']]))->setFactory([new Reference('__external__.array_object_factory'), 'exchangeArray'])
+        $baseContainer->setDefinition(
+            'array_object',
+            (new Definition(\ArrayObject::class, [['new' => 'new']]))
+                ->setFactory([new Reference('__external__.array_object_factory'), 'exchangeArray'])
+                ->setPublic(true)
         );
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);
@@ -142,9 +145,11 @@ public function it_resolves_cross_container_parameters_in_service_definition_arr
         $externalContainer->setParameter('parameter', '42');
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [
-            ['parameter' => '%__external__.parameter%'],
-        ]));
+        $baseContainer->setDefinition(
+            'array_object',
+            (new Definition(\ArrayObject::class, [['parameter' => '%__external__.parameter%']]))
+                ->setPublic(true)
+        );
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);
 
@@ -190,10 +195,15 @@ public function it_resolves_cross_container_escaped_parameters_symfony_kernel():
     public function it_resolves_cross_container_references_in_method_calls(): void
     {
         $externalContainer = new ContainerBuilder();
-        $externalContainer->setDefinition('array_object', new Definition(\ArrayObject::class, [['foo' => 'bar']]));
+        $externalContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [['foo' => 'bar']]))->setPublic(true));
 
         $baseContainer = new ContainerBuilder();
-        $baseContainer->setDefinition('array_object', (new Definition(\ArrayObject::class, [[]]))->addMethodCall('exchangeArray', [new Reference('__external__.array_object')]));
+        $baseContainer->setDefinition(
+            'array_object',
+            (new Definition(\ArrayObject::class, [[]]))
+                ->addMethodCall('exchangeArray', [new Reference('__external__.array_object')])
+                ->setPublic(true)
+        );
 
         $this->buildContainerWithDependencies($baseContainer, ['external' => $externalContainer]);