diff --git a/drush.php b/drush.php
index b6cb544bea..cd00e708c8 100755
--- a/drush.php
+++ b/drush.php
@@ -134,7 +134,7 @@
 // Preflight and run
 $preflight = new Preflight($environment);
 $di = new DependencyInjection();
-$di->desiredHandlers(['errorHandler', 'shutdownHandler']);
+$di->desiredHandlers(['errorHandler']);
 $runtime = new Runtime($preflight, $di);
 $status_code = $runtime->run($_SERVER['argv']);
 
diff --git a/src/Runtime/DependencyInjection.php b/src/Runtime/DependencyInjection.php
index 65cb9e5219..4743dc359c 100644
--- a/src/Runtime/DependencyInjection.php
+++ b/src/Runtime/DependencyInjection.php
@@ -146,9 +146,8 @@ protected function addDrushServices($container, ClassLoader $loader, DrushDrupal
             ->addMethodCall('addSearchLocation', ['CommandFiles'])
             ->addMethodCall('setSearchPattern', ['#.*(Commands|CommandFile).php$#']);
 
-        // Error and Shutdown handlers
+        // Error handler
         Robo::addShared($container, 'errorHandler', 'Drush\Runtime\ErrorHandler');
-        Robo::addShared($container, 'shutdownHandler', 'Drush\Runtime\ShutdownHandler');
 
         // Add inflectors. @see \Drush\Boot\BaseBoot::inflect
         $container->inflector(SiteAliasManagerAwareInterface::class)
diff --git a/src/Runtime/Runtime.php b/src/Runtime/Runtime.php
index 288a9cff04..71c5454869 100644
--- a/src/Runtime/Runtime.php
+++ b/src/Runtime/Runtime.php
@@ -4,11 +4,11 @@
 
 namespace Drush\Runtime;
 
-use Symfony\Component\Console\Output\ConsoleOutput;
 use Drush\Application;
 use Drush\Commands\DrushCommands;
 use Drush\Drush;
 use Drush\Preflight\Preflight;
+use Symfony\Component\Console\Output\ConsoleOutput;
 
 /**
  * Control the Drush runtime environment
@@ -21,8 +21,9 @@
  */
 class Runtime
 {
+
+    // Shutdown handling removed from Drush, but 3rd party commandfiles may add it back.
     const DRUSH_RUNTIME_COMPLETED_NAMESPACE = 'runtime.execution.completed';
-    const DRUSH_RUNTIME_EXIT_CODE_NAMESPACE = 'runtime.exit_code';
 
     public function __construct(protected Preflight $preflight, protected DependencyInjection $di)
     {
@@ -109,40 +110,19 @@ protected function doRun($argv, $output): int
         // Bootstrap: bootstrap site to the level requested by the command (via a 'post-init' hook)
         $status = $application->run($input, $output);
 
-        // Placate the Drush shutdown handler.
+        // Placate the Drush shutdown handler which can be provided via custom commandfile.
         Runtime::setCompleted();
-        Runtime::setExitCode($status);
 
         return $status;
     }
 
     /**
      * Mark the current request as having completed successfully.
+     *
+     * Shutdown handling removed from Drush, but 3rd party commandfiles may add it back.
      */
     public static function setCompleted(): void
     {
         Drush::config()->set(self::DRUSH_RUNTIME_COMPLETED_NAMESPACE, true);
     }
-
-    /**
-     * Mark the exit code for current request.
-     *
-     * @deprecated
-     *   Was used by backend.inc
-     */
-    public static function setExitCode(int $code): void
-    {
-        Drush::config()->set(self::DRUSH_RUNTIME_EXIT_CODE_NAMESPACE, $code);
-    }
-
-    /**
-     * Get the exit code for current request.
-     *
-     * @deprecated
-     *   Was used by backend.inc
-     */
-    public static function exitCode()
-    {
-        return Drush::config()->get(self::DRUSH_RUNTIME_EXIT_CODE_NAMESPACE, 0);
-    }
 }
diff --git a/src/Runtime/ShutdownHandler.php b/src/Runtime/ShutdownHandler.php
deleted file mode 100644
index 8e0494ba4c..0000000000
--- a/src/Runtime/ShutdownHandler.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Drush\Runtime;
-
-use Drush\Commands\DrushCommands;
-use Drush\Drush;
-use Psr\Log\LoggerAwareInterface;
-use Psr\Log\LoggerAwareTrait;
-
-/**
- * Drush's shutdown handler
- *
- * If the command is being executed with the --backend option, the script
- * will return a json string containing the options and log information
- * used by the script.
- *
- * The command will exit with '0' if it was successfully executed, and the
- * result of Runtime::exitCode() if it wasn't.
- *
- */
-class ShutdownHandler implements LoggerAwareInterface, HandlerInterface
-{
-    use LoggerAwareTrait;
-
-    public function installHandler(): void
-    {
-        register_shutdown_function([$this, 'shutdownHandler']);
-    }
-
-    public function shutdownHandler(): void
-    {
-        // Avoid doing anything if our container has not been initialized yet.
-        if (!Drush::hasContainer()) {
-            return;
-        }
-
-        if (!Drush::config()->get(Runtime::DRUSH_RUNTIME_COMPLETED_NAMESPACE)) {
-            Drush::logger()->warning('Drush command terminated abnormally.');
-            // Make sure that we will return an error code when we exit,
-            // even if the code that got us here did not.
-            if (!Runtime::exitCode()) {
-                Runtime::setExitCode(DrushCommands::EXIT_FAILURE);
-            }
-        }
-
-        // This way returnStatus() will always be the last shutdown function (unless other shutdown functions register shutdown functions...)
-        // and won't prevent other registered shutdown functions (IE from numerous cron methods) from running by calling exit() before they get a chance.
-        register_shutdown_function([$this, 'returnStatus']);
-    }
-
-    /**
-     * @deprecated. This function will be removed in Drush 10. Throw an exception to indicate an error.
-     */
-    public function returnStatus(): never
-    {
-        exit(Runtime::exitCode());
-    }
-}
diff --git a/tests/functional/ShutdownAndErrorHandlerTest.php b/tests/functional/ShutdownAndErrorHandlerTest.php
index e869fe67db..0bcba1b28d 100644
--- a/tests/functional/ShutdownAndErrorHandlerTest.php
+++ b/tests/functional/ShutdownAndErrorHandlerTest.php
@@ -20,10 +20,10 @@ class ShutdownAndErrorHandlerTest extends CommandUnishTestCase
      */
     public function testShutdownFunctionAbruptExit()
     {
-        // Run some garbage php with a syntax error.
-        $this->drush(PhpCommands::EVAL, ['exit(0);'], [], null, null, DrushCommands::EXIT_FAILURE);
-
-        $this->assertStringContainsString("Drush command terminated abnormally.", $this->getErrorOutput(), 'Error handler did not log a message.');
+        // Run some garbage php with a syntax error and assert correct exit code.
+        $this->drush(PhpCommands::EVAL, ['exit(1);'], [], null, null, DrushCommands::EXIT_FAILURE);
+        // Placate phpunit. If above succeeds we are done here.
+        $this->addToAssertionCount(1);
     }
 
     /**
@@ -46,9 +46,9 @@ public function testShutdownFunctionExitCodePassedThrough()
     public function testShutdownFunctionPHPError()
     {
         // Run some garbage php with a syntax error.
-        $this->drush(PhpCommands::EVAL, ['\Drush\Drush::setContainer("string is the wrong type to pass here");'], [], null, null, PHP_MAJOR_VERSION == 5 ? 255 : DrushCommands::EXIT_FAILURE);
-
-        $this->assertStringContainsString("Drush command terminated abnormally.", $this->getErrorOutput(), 'Error handler did not log a message.');
+        $this->drush(PhpCommands::EVAL, ['\Drush\Drush::setContainer("string is the wrong type to pass here");'], [], null, null, DrushCommands::EXIT_FAILURE);
+        // Placate phpunit. If above succeeds we are done here.
+        $this->addToAssertionCount(1);
     }
 
     /**
@@ -58,12 +58,6 @@ public function testErrorHandler()
     {
         // Access a missing array element
         $this->drush(PhpCommands::EVAL, ['$a = []; print $a["b"];']);
-
-        if (empty($this->logLevel()) && PHP_MAJOR_VERSION <= 7) {
-            $this->assertEquals('', $this->getErrorOutput(), 'Error handler did not suppress deprecated message.');
-        } else {
-            $msg = PHP_MAJOR_VERSION >= 8 ? 'Undefined array key "b" PhpCommands.php' : 'Undefined index: b PhpCommands.php';
-            $this->assertStringContainsString($msg, $this->getErrorOutput());
-        }
+        $this->assertStringContainsString('Undefined array key "b" PhpCommands.php', $this->getErrorOutput());
     }
 }