diff --git a/src/Bootstrappers/BootSubscribers.php b/src/Bootstrappers/BootSubscribers.php
index c38b873b..8a2df311 100644
--- a/src/Bootstrappers/BootSubscribers.php
+++ b/src/Bootstrappers/BootSubscribers.php
@@ -21,7 +21,6 @@ final class BootSubscribers implements Bootstrapper
      * @var array<int, class-string<Subscriber>>
      */
     private const SUBSCRIBERS = [
-        Subscribers\EnsureConfigurationIsValid::class,
         Subscribers\EnsureConfigurationIsAvailable::class,
         Subscribers\EnsureIgnorableTestCasesAreIgnored::class,
         Subscribers\EnsureKernelDumpIsFlushed::class,
diff --git a/src/Exceptions/AttributeNotSupportedYet.php b/src/Exceptions/AttributeNotSupportedYet.php
deleted file mode 100644
index d34262f6..00000000
--- a/src/Exceptions/AttributeNotSupportedYet.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Pest\Exceptions;
-
-use InvalidArgumentException;
-use NunoMaduro\Collision\Contracts\RenderlessEditor;
-use NunoMaduro\Collision\Contracts\RenderlessTrace;
-use Symfony\Component\Console\Exception\ExceptionInterface;
-
-/**
- * @internal
- */
-final class AttributeNotSupportedYet extends InvalidArgumentException implements ExceptionInterface, RenderlessEditor, RenderlessTrace
-{
-    /**
-     * Creates a new Exception instance.
-     */
-    public function __construct(string $attribute, string $value)
-    {
-        parent::__construct(sprintf('The PHPUnit attribute `%s` with value `%s` is not supported yet.', $attribute, $value));
-    }
-}
diff --git a/src/Subscribers/EnsureConfigurationIsValid.php b/src/Subscribers/EnsureConfigurationIsValid.php
deleted file mode 100644
index 8c5c615b..00000000
--- a/src/Subscribers/EnsureConfigurationIsValid.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Pest\Subscribers;
-
-use Pest\Exceptions\AttributeNotSupportedYet;
-use PHPUnit\Event\TestRunner\Configured;
-use PHPUnit\Event\TestRunner\ConfiguredSubscriber;
-
-/**
- * @internal
- */
-final class EnsureConfigurationIsValid implements ConfiguredSubscriber
-{
-    /**
-     * Runs the subscriber.
-     */
-    public function notify(Configured $event): void
-    {
-        $configuration = $event->configuration();
-
-        if ($configuration->processIsolation()) {
-            throw new AttributeNotSupportedYet('processIsolation', 'true');
-        }
-    }
-}