diff --git a/composer.json b/composer.json
index 6c62dbd..61528aa 100644
--- a/composer.json
+++ b/composer.json
@@ -4,13 +4,13 @@
     "license": "Apache-2.0",
     "minimum-stability": "stable",
     "require": {
+        "php": ">=7.4",
         "google/cloud-logging": "^1.16",
         "google/gax": "^1.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8|^5.0|^8.0",
-        "yoast/phpunit-polyfills": "^1.0",
-        "phpspec/prophecy": "^1.10.3",
+        "phpunit/phpunit": "^9.0",
+        "phpspec/prophecy-phpunit": "^2.0",
         "google/cloud-core": "^1.39"
     },
     "suggest": {
diff --git a/tests/Unit/BootstrapTest.php b/tests/Unit/BootstrapTest.php
index 2e9ef77..4e598c9 100644
--- a/tests/Unit/BootstrapTest.php
+++ b/tests/Unit/BootstrapTest.php
@@ -21,8 +21,9 @@
 use Google\Cloud\ErrorReporting\Bootstrap;
 use Google\Cloud\ErrorReporting\MockValues;
 use Google\Cloud\Logging\PsrLogger;
+use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
-use Yoast\PHPUnitPolyfills\TestCases\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
 
 //@codingStandardsIgnoreStart
 require_once __DIR__ . '/fakeGlobalFunctions.php';
@@ -33,11 +34,13 @@
  */
 class BootstrapTest extends TestCase
 {
+    use ProphecyTrait;
+
 
     private $psrBatchLogger;
     private $metadataProvider;
 
-    public function set_up()
+    public function setUp(): void
     {
         $this->psrBatchLogger = $this->prophesize(PsrLogger::class);
     }