diff --git a/LICENSE b/LICENSE
index 460b317..d1524fe 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2016 Matthias Noback
+Copyright (c) Matthias Noback
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index a599cb3..a15163d 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ class OrderSeats
 And use it like this:
 
 ```php
-$form = $this->factory->create(new OrderSeatsFormType());
+$form = $this->factory->create(OrderSeatsFormType::class);
 $form->submit($request);
 $command = $form->getData();
 $command->id = Uuid::uuid4();
@@ -74,7 +74,7 @@ The MIT License (MIT). Please see [License File](LICENSE.md) for more informatio
 [ico-version]: https://img.shields.io/packagist/v/matthiasnoback/convenient-immutability.svg?style=flat-square
 [ico-license]: https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square
 [ico-coveralls]: https://img.shields.io/coveralls/matthiasnoback/convenient-immutability.svg?style=flat-square
-[ico-travis]: https://img.shields.io/travis/matthiasnoback/convenient-immutability.svg?style=flat-square 
+[ico-travis]: https://img.shields.io/travis/matthiasnoback/convenient-immutability.svg?style=flat-square
 [ico-downloads]: https://img.shields.io/packagist/dt/matthiasnoback/convenient-immutability.svg?style=flat-square
 
 [link-packagist]: https://packagist.org/packages/matthiasnoback/convenient-immutability
@@ -82,4 +82,4 @@ The MIT License (MIT). Please see [License File](LICENSE.md) for more informatio
 [link-travis]: https://travis-ci.org/matthiasnoback/convenient-immutability
 [link-downloads]: https://packagist.org/packages/matthiasnoback/convenient-immutability
 [link-author]: https://github.com/matthiasnoback
-[link-contributors]: ../../contributors
\ No newline at end of file
+[link-contributors]: ../../contributors
diff --git a/src/Immutable.php b/src/Immutable.php
index 2ae6562..28dc1b1 100644
--- a/src/Immutable.php
+++ b/src/Immutable.php
@@ -2,6 +2,10 @@
 
 namespace ConvenientImmutability;
 
+use LogicException;
+use ReflectionObject;
+use const PHP_VERSION_ID;
+
 trait Immutable
 {
     private $_defaultValues = [];
@@ -17,7 +21,7 @@ trait Immutable
     public function __construct()
     {
         // take over all user-defined non-static properties
-        foreach ((new \ReflectionObject($this))->getProperties() as $property) {
+        foreach ((new ReflectionObject($this))->getProperties() as $property) {
             $propertyName = $property->getName();
 
             if (isset(self::$_doNotTakeOverProperties[$propertyName]) || $property->isStatic()) {
@@ -25,7 +29,7 @@ public function __construct()
             }
 
             $this->_userDefinedProperties[$propertyName] = true;
-            if (\PHP_VERSION_ID < 70400 || $property->isInitialized($this)) {
+            if (PHP_VERSION_ID < 70400 || $property->isInitialized($this)) {
                 $this->_defaultValues[$propertyName] = $property->getValue($this);
             }
             unset($this->{$propertyName});
@@ -35,11 +39,11 @@ public function __construct()
     final public function __set($name, $value)
     {
         if (!isset($this->_userDefinedProperties[$name])) {
-            throw new \LogicException('Unknown property "' . $name . '"');
+            throw new LogicException('Unknown property "' . $name . '"');
         }
 
         if (array_key_exists($name, $this->_userDefinedValues)) {
-            throw new \LogicException('You can not overwrite the value for property "' . $name . '"');
+            throw new LogicException('You can not overwrite the value for property "' . $name . '"');
         }
 
         $this->_userDefinedValues[$name] = $value;
@@ -48,7 +52,7 @@ final public function __set($name, $value)
     final public function __get($name)
     {
         if (!isset($this->_userDefinedProperties[$name])) {
-            throw new \LogicException('Unknown property "' . $name . '"');
+            throw new LogicException('Unknown property "' . $name . '"');
         }
 
         if (array_key_exists($name, $this->_userDefinedValues)) {
diff --git a/test/FormIntegrationTest.php b/test/FormIntegrationTest.php
index a991e8a..100ede3 100644
--- a/test/FormIntegrationTest.php
+++ b/test/FormIntegrationTest.php
@@ -7,12 +7,12 @@
 use Ramsey\Uuid\Uuid;
 use Symfony\Component\Form\Test\TypeTestCase;
 
-class FormIntegrationTest extends TypeTestCase
+final class FormIntegrationTest extends TypeTestCase
 {
     /**
      * @test
      */
-    public function it_works_with_a_standard_use_case_for_command_objects()
+    public function it_works_with_a_standard_use_case_for_command_objects(): void
     {
         $id = Uuid::uuid4();
         $form = $this->factory->create(OrderSeatsFormType::class);
diff --git a/test/ImmutableTraitTest.php b/test/ImmutableTraitTest.php
index f791730..ef291ab 100644
--- a/test/ImmutableTraitTest.php
+++ b/test/ImmutableTraitTest.php
@@ -8,12 +8,12 @@
 use LogicException;
 use PHPUnit\Framework\TestCase;
 
-class ImmutableTraitTest extends TestCase
+final class ImmutableTraitTest extends TestCase
 {
     /**
      * @return array
      */
-    public function objectProvider()
+    public function objectProvider(): array
     {
         $foo = new Foo();
 
@@ -32,7 +32,7 @@ public function objectProvider()
      * @test
      * @dataProvider objectProvider
      */
-    public function it_allows_one_assignment_per_property(Foo $foo)
+    public function it_allows_one_assignment_per_property(Foo $foo): void
     {
         $foo->bar = 1;
         $foo->baz = 2;
@@ -45,7 +45,7 @@ public function it_allows_one_assignment_per_property(Foo $foo)
      * @test
      * @dataProvider objectProvider
      */
-    public function it_fails_when_a_property_gets_reassigned(Foo $foo)
+    public function it_fails_when_a_property_gets_reassigned(Foo $foo): void
     {
         $foo->bar = 1;
 
@@ -59,7 +59,7 @@ public function it_fails_when_a_property_gets_reassigned(Foo $foo)
      * @test
      * @dataProvider objectProvider
      */
-    public function it_fails_to_assign_values_to_undefined_properties(Foo $foo)
+    public function it_fails_to_assign_values_to_undefined_properties(Foo $foo): void
     {
         $this->expectException(LogicException::class);
         $foo->bang = 1;
@@ -69,7 +69,7 @@ public function it_fails_to_assign_values_to_undefined_properties(Foo $foo)
      * @test
      * @dataProvider objectProvider
      */
-    public function it_fails_to_retrieve_values_from_undefined_properties(Foo $foo)
+    public function it_fails_to_retrieve_values_from_undefined_properties(Foo $foo): void
     {
         $this->expectException(LogicException::class);
         $foo->bang;
@@ -79,7 +79,7 @@ public function it_fails_to_retrieve_values_from_undefined_properties(Foo $foo)
      * @test
      * @dataProvider objectProvider
      */
-    public function it_returns_null_for_properties_that_have_no_assigned_value(Foo $foo)
+    public function it_returns_null_for_properties_that_have_no_assigned_value(Foo $foo): void
     {
         $this->assertSame(null, $foo->bar);
     }
@@ -88,7 +88,7 @@ public function it_returns_null_for_properties_that_have_no_assigned_value(Foo $
      * @test
      * @dataProvider objectProvider
      */
-    public function it_returns_the_default_attribute_value_of_properties_that_have_no_assigned_value(Foo $foo)
+    public function it_returns_the_default_attribute_value_of_properties_that_have_no_assigned_value(Foo $foo): void
     {
         $this->assertSame([], $foo->bazzes);
     }
@@ -97,7 +97,7 @@ public function it_returns_the_default_attribute_value_of_properties_that_have_n
      * @test
      * @dataProvider objectProvider
      */
-    public function it_should_have_the_same_values_after_deserialization(Foo $foo)
+    public function it_should_have_the_same_values_after_deserialization(Foo $foo): void
     {
         $foo->bar = 'bar';
         $foo->baz = 1;
diff --git a/test/Resources/OrderSeats.php b/test/Resources/OrderSeats.php
index ef08b7c..960fcd6 100644
--- a/test/Resources/OrderSeats.php
+++ b/test/Resources/OrderSeats.php
@@ -4,7 +4,7 @@
 
 use ConvenientImmutability\Immutable;
 
-class OrderSeats
+final class OrderSeats
 {
     use Immutable;
 
diff --git a/test/Resources/OrderSeatsFormType.php b/test/Resources/OrderSeatsFormType.php
index 994e03c..6926878 100644
--- a/test/Resources/OrderSeatsFormType.php
+++ b/test/Resources/OrderSeatsFormType.php
@@ -7,7 +7,7 @@
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
-class OrderSeatsFormType extends AbstractType
+final class OrderSeatsFormType extends AbstractType
 {
     public function buildForm(FormBuilderInterface $builder, array $options)
     {