diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5b44684..099fbea 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,7 +34,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ['7.3', '7.4', '8.0', '8.1']
+        php: ['5.4', '5.5', '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1']
 
     name: PHP ${{ matrix.php }}
 
diff --git a/README.md b/README.md
index ee0e1b0..f05bfd5 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,13 @@ composer require --dev phpspec/prophecy-phpunit
 
 You can read more about Composer on its [official webpage](https://getcomposer.org).
 
+> :bulb: The package can be safely required and used on PHP 5.4 to current in combination with PHPUnit 4.8.36/5.7.21 to current.
+>
+> When the PHPUnit `prophesize()` method is natively available and not deprecated (PHPUnit 4.8 - 9.0), the PHPUnit
+> native functionality will be used.
+> For PHPUnit 9.1 and higher, the extension will kick in and polyfill the functionality which was deprecated in PHPUnit.
+
+
 ## How to use it
 
 The trait ``ProphecyTrait`` provides a method ``prophesize($classOrInterface = null)`` to use Prophecy.
diff --git a/composer.json b/composer.json
index 2c48d3b..d085180 100644
--- a/composer.json
+++ b/composer.json
@@ -14,9 +14,9 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": "^7.3 || ^8",
+        "php": "^5.4 || ^7.0 || ^8.0",
         "phpspec/prophecy": "^1.3",
-        "phpunit/phpunit":"^9.1"
+        "phpunit/phpunit": "^4.8.36 || ^5.7.21 || ^6.0 || ^7.0 || ^8.0 || ^9.1"
     },
     "autoload": {
         "psr-4": {
diff --git a/fixtures/Success.php b/fixtures/Success.php
index 9fdd98c..9e2248e 100644
--- a/fixtures/Success.php
+++ b/fixtures/Success.php
@@ -5,6 +5,10 @@
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
 
+/**
+ * {@internal The code in this file must be PHP cross-version compatible for PHP 5.4 - current
+ * as this test is also used in the AvailabilityTest.}
+ */
 class Success extends TestCase
 {
     use ProphecyTrait;
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9c251d1..4385840 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -3,7 +3,8 @@
 <phpunit colors="true" bootstrap="vendor/autoload.php">
     <testsuites>
         <testsuite name="Prophecy PhpUnit Test Suite">
-            <directory suffix="Test.php">./tests/</directory>
+            <directory suffix="Test.php">./tests/Availability</directory>
+            <directory phpVersion="7.3.0" phpVersionOperator=">=" suffix="Test.php">./tests/</directory>
         </testsuite>
     </testsuites>
 
diff --git a/src/ProphecyTrait.actual.php b/src/ProphecyTrait.actual.php
new file mode 100644
index 0000000..7fb7d54
--- /dev/null
+++ b/src/ProphecyTrait.actual.php
@@ -0,0 +1,110 @@
+<?php declare(strict_types=1);
+
+namespace Prophecy\PhpUnit;
+
+use PHPUnit\Framework\AssertionFailedError;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Exception\Doubler\DoubleException;
+use Prophecy\Exception\Doubler\InterfaceNotFoundException;
+use Prophecy\Exception\Prediction\PredictionException;
+use Prophecy\Prophecy\MethodProphecy;
+use Prophecy\Prophecy\ObjectProphecy;
+use Prophecy\Prophet;
+
+/**
+ * @mixin TestCase
+ */
+trait ProphecyTrait
+{
+    /**
+     * @var Prophet|null
+     *
+     * @internal
+     */
+    private $prophet;
+
+    /**
+     * @var bool
+     *
+     * @internal
+     */
+    private $prophecyAssertionsCounted = false;
+
+    /**
+     * @throws DoubleException
+     * @throws InterfaceNotFoundException
+     *
+     * @psalm-param class-string|null $classOrInterface
+     */
+    protected function prophesize(?string $classOrInterface = null): ObjectProphecy
+    {
+        if (\is_string($classOrInterface)) {
+            \assert($this instanceof TestCase);
+            $this->recordDoubledType($classOrInterface);
+        }
+
+        return $this->getProphet()->prophesize($classOrInterface);
+    }
+
+    /**
+     * @postCondition
+     */
+    protected function verifyProphecyDoubles(): void
+    {
+        if ($this->prophet === null) {
+            return;
+        }
+
+        try {
+            $this->prophet->checkPredictions();
+        } catch (PredictionException $e) {
+            throw new AssertionFailedError($e->getMessage());
+        } finally {
+            $this->countProphecyAssertions();
+        }
+    }
+
+    /**
+     * @after
+     */
+    protected function tearDownProphecy(): void
+    {
+        if (null !== $this->prophet && !$this->prophecyAssertionsCounted) {
+            // Some Prophecy assertions may have been done in tests themselves even when a failure happened before checking mock objects.
+            $this->countProphecyAssertions();
+        }
+
+        $this->prophet = null;
+    }
+
+    /**
+     * @internal
+     */
+    private function countProphecyAssertions(): void
+    {
+        \assert($this instanceof TestCase);
+        $this->prophecyAssertionsCounted = true;
+
+        foreach ($this->prophet->getProphecies() as $objectProphecy) {
+            foreach ($objectProphecy->getMethodProphecies() as $methodProphecies) {
+                foreach ($methodProphecies as $methodProphecy) {
+                    \assert($methodProphecy instanceof MethodProphecy);
+
+                    $this->addToAssertionCount(\count($methodProphecy->getCheckedPredictions()));
+                }
+            }
+        }
+    }
+
+    /**
+     * @internal
+     */
+    private function getProphet(): Prophet
+    {
+        if ($this->prophet === null) {
+            $this->prophet = new Prophet;
+        }
+
+        return $this->prophet;
+    }
+}
diff --git a/src/ProphecyTrait.empty.php b/src/ProphecyTrait.empty.php
new file mode 100644
index 0000000..85c0d89
--- /dev/null
+++ b/src/ProphecyTrait.empty.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Prophecy\PhpUnit;
+
+/**
+ * Prophecy trait for use with PHPUnit 4.x - 9.0.
+ *
+ * As this trait is empty, calls to `prophesize()` will automatically fall through
+ * to PHPUnit itself and will use the PHPUnit native `prophesize()` method.
+ *
+ * {@internal The code in this file must be PHP cross-version compatible for PHP 5.4 - current!}
+ *
+ * @mixin TestCase
+ */
+trait ProphecyTrait
+{
+}
diff --git a/src/ProphecyTrait.php b/src/ProphecyTrait.php
index 7fb7d54..fddb4c2 100644
--- a/src/ProphecyTrait.php
+++ b/src/ProphecyTrait.php
@@ -1,110 +1,43 @@
-<?php declare(strict_types=1);
+<?php
 
 namespace Prophecy\PhpUnit;
 
-use PHPUnit\Framework\AssertionFailedError;
-use PHPUnit\Framework\TestCase;
-use Prophecy\Exception\Doubler\DoubleException;
-use Prophecy\Exception\Doubler\InterfaceNotFoundException;
-use Prophecy\Exception\Prediction\PredictionException;
-use Prophecy\Prophecy\MethodProphecy;
-use Prophecy\Prophecy\ObjectProphecy;
-use Prophecy\Prophet;
+use PHPUnit\Runner\Version;
+use PHPUnit_Runner_Version;
 
 /**
- * @mixin TestCase
+ * Load the prophecy trait.
+ *
+ * {@internal The code in this file must be PHP cross-version compatible for PHP 5.4 - current!}
  */
-trait ProphecyTrait
-{
-    /**
-     * @var Prophet|null
-     *
-     * @internal
-     */
-    private $prophet;
-
-    /**
-     * @var bool
-     *
-     * @internal
-     */
-    private $prophecyAssertionsCounted = false;
-
-    /**
-     * @throws DoubleException
-     * @throws InterfaceNotFoundException
-     *
-     * @psalm-param class-string|null $classOrInterface
-     */
-    protected function prophesize(?string $classOrInterface = null): ObjectProphecy
-    {
-        if (\is_string($classOrInterface)) {
-            \assert($this instanceof TestCase);
-            $this->recordDoubledType($classOrInterface);
-        }
-
-        return $this->getProphet()->prophesize($classOrInterface);
-    }
-
-    /**
-     * @postCondition
-     */
-    protected function verifyProphecyDoubles(): void
-    {
-        if ($this->prophet === null) {
-            return;
-        }
 
-        try {
-            $this->prophet->checkPredictions();
-        } catch (PredictionException $e) {
-            throw new AssertionFailedError($e->getMessage());
-        } finally {
-            $this->countProphecyAssertions();
-        }
+/**
+ * Retrieve the PHPUnit version id.
+ *
+ * As both the pre-PHPUnit 6 class, as well as the PHPUnit 6+ class contain the `id()` function,
+ * this should work independently of whether or not another library may have aliased the class.
+ *
+ * @internal
+ *
+ * @return string Version number as a string.
+ */
+function getPHPUnitVersion()
+{
+    if (\class_exists('\PHPUnit\Runner\Version')) {
+        return Version::id();
     }
 
-    /**
-     * @after
-     */
-    protected function tearDownProphecy(): void
-    {
-        if (null !== $this->prophet && !$this->prophecyAssertionsCounted) {
-            // Some Prophecy assertions may have been done in tests themselves even when a failure happened before checking mock objects.
-            $this->countProphecyAssertions();
-        }
-
-        $this->prophet = null;
+    if (\class_exists('\PHPUnit_Runner_Version')) {
+        return PHPUnit_Runner_Version::id();
     }
 
-    /**
-     * @internal
-     */
-    private function countProphecyAssertions(): void
-    {
-        \assert($this instanceof TestCase);
-        $this->prophecyAssertionsCounted = true;
-
-        foreach ($this->prophet->getProphecies() as $objectProphecy) {
-            foreach ($objectProphecy->getMethodProphecies() as $methodProphecies) {
-                foreach ($methodProphecies as $methodProphecy) {
-                    \assert($methodProphecy instanceof MethodProphecy);
-
-                    $this->addToAssertionCount(\count($methodProphecy->getCheckedPredictions()));
-                }
-            }
-        }
-    }
+    return '0';
+}
 
-    /**
-     * @internal
-     */
-    private function getProphet(): Prophet
-    {
-        if ($this->prophet === null) {
-            $this->prophet = new Prophet;
-        }
 
-        return $this->prophet;
-    }
+if (\version_compare(getPHPUnitVersion(), '9.1.0', '>=')) {
+    // PHPUnit >= 9.1.0.
+    require_once __DIR__ . '/ProphecyTrait.actual.php';
+} else {
+    require_once __DIR__ . '/ProphecyTrait.empty.php';
 }
diff --git a/tests/Availability/AvailabilityTest.php b/tests/Availability/AvailabilityTest.php
new file mode 100644
index 0000000..51f1ac5
--- /dev/null
+++ b/tests/Availability/AvailabilityTest.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Prophecy\PhpUnit\Tests\Availability;
+
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Prophecy\PhpUnit\Tests\Fixtures\Success;
+
+/**
+ * Testing that the autoloading of the empty `ProphecyTrait` trait for PHPUnit 4.x - 9.0 works correctly.
+ *
+ * {@internal The code in this file must be PHP cross-version compatible for PHP 5.4 - current!}
+ *
+ * @coversNothing
+ */
+final class AvailabilityTest extends TestCase
+{
+    /**
+     * @before
+     */
+    protected function declareTestsuiteConstant()
+    {
+        // Define the constant because our tests are running PHPUnit test cases themselves
+        if (!\defined('PHPUNIT_TESTSUITE')) {
+            \define('PHPUNIT_TESTSUITE', true);
+        }
+    }
+
+    public function testSuccessfullyCallingProphesizeMethod()
+    {
+        $this->assertTrue(trait_exists('Prophecy\PhpUnit\ProphecyTrait'), 'Failed to assert that the ProphecyTrait is available');
+
+        $test = new Success('testMethod');
+
+        $result = $test->run();
+
+        $this->assertSame(0, $result->errorCount(), 'Error count is not 0');
+        $this->assertSame(0, $result->failureCount(), 'Failure count is not 0');
+        $this->assertCount(1, $result, 'Result is not 1');
+        $this->assertSame(1, $test->getNumAssertions(), 'Number of assertions is not 1');
+    }
+}
diff --git a/tests/ProphecyTraitTest.php b/tests/ProphecyTraitTest.php
index 6e6a168..afb0a0d 100644
--- a/tests/ProphecyTraitTest.php
+++ b/tests/ProphecyTraitTest.php
@@ -11,6 +11,8 @@
 
 /**
  * @covers \Prophecy\PhpUnit\ProphecyTrait
+ *
+ * @requires PHPUnit 9.1
  */
 final class ProphecyTraitTest extends TestCase
 {