diff --git a/UPGRADE.md b/UPGRADE.md
index ef8b5c605f..cad3628dbe 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,5 +1,11 @@
 # Upgrade to 4.0
 
+## Require implementation of `OutputWalker`, remove `SqlWalker::getExecutor()`
+
+The `SqlWalker::getExecutor()` method is removed. Output walkers should
+implement the `\Doctrine\ORM\Query\OutputWalker` interface and create
+`Doctrine\ORM\Query\Exec\SqlFinalizer` instances.
+
 ## Remove `DatabaseDriver`
 
 The class `Doctrine\ORM\Mapping\Driver\DatabaseDriver` is removed.
diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index bf151dcafb..88526e4592 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -896,9 +896,6 @@
     <ArgumentTypeCoercion>
       <code><![CDATA[$stringPattern]]></code>
     </ArgumentTypeCoercion>
-    <DeprecatedMethod>
-      <code><![CDATA[setSqlExecutor]]></code>
-    </DeprecatedMethod>
     <InvalidNullableReturnType>
       <code><![CDATA[AST\SelectStatement|AST\UpdateStatement|AST\DeleteStatement]]></code>
     </InvalidNullableReturnType>
diff --git a/src/Query.php b/src/Query.php
index 890b2a9dfa..b7dae94d10 100644
--- a/src/Query.php
+++ b/src/Query.php
@@ -7,14 +7,11 @@
 use Doctrine\DBAL\LockMode;
 use Doctrine\DBAL\Result;
 use Doctrine\DBAL\Types\Type;
-use Doctrine\Deprecations\Deprecation;
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Query\AST\DeleteStatement;
 use Doctrine\ORM\Query\AST\SelectStatement;
 use Doctrine\ORM\Query\AST\UpdateStatement;
 use Doctrine\ORM\Query\Exec\AbstractSqlExecutor;
-use Doctrine\ORM\Query\Exec\SqlFinalizer;
-use Doctrine\ORM\Query\OutputWalker;
 use Doctrine\ORM\Query\Parameter;
 use Doctrine\ORM\Query\ParameterTypeInferer;
 use Doctrine\ORM\Query\Parser;
@@ -30,7 +27,6 @@
 use function count;
 use function get_debug_type;
 use function in_array;
-use function is_a;
 use function ksort;
 use function md5;
 use function reset;
@@ -665,31 +661,10 @@ protected function getQueryCacheId(): string
     {
         ksort($this->hints);
 
-        if (! $this->hasHint(self::HINT_CUSTOM_OUTPUT_WALKER)) {
-            // Assume Parser will create the SqlOutputWalker; save is_a call, which might trigger a class load
-            $firstAndMaxResult = '';
-        } else {
-            $outputWalkerClass = $this->getHint(self::HINT_CUSTOM_OUTPUT_WALKER);
-            if (is_a($outputWalkerClass, OutputWalker::class, true)) {
-                $firstAndMaxResult = '';
-            } else {
-                Deprecation::trigger(
-                    'doctrine/orm',
-                    'https://github.com/doctrine/orm/pull/11188/',
-                    'Your output walker class %s should implement %s in order to provide a %s. This also means the output walker should not use the query firstResult/maxResult values, which should be read from the query by the SqlFinalizer only.',
-                    $outputWalkerClass,
-                    OutputWalker::class,
-                    SqlFinalizer::class,
-                );
-                $firstAndMaxResult = '&firstResult=' . $this->firstResult . '&maxResult=' . $this->maxResults;
-            }
-        }
-
         return md5(
             $this->getDQL() . serialize($this->hints) .
             '&platform=' . get_debug_type($this->getEntityManager()->getConnection()->getDatabasePlatform()) .
             ($this->em->hasFilters() ? $this->em->getFilters()->getHash() : '') .
-            $firstAndMaxResult .
             '&hydrationMode=' . $this->hydrationMode . '&types=' . serialize($this->parsedTypes) . 'DOCTRINE_QUERY_CACHE_SALT',
         );
     }
diff --git a/src/Query/Parser.php b/src/Query/Parser.php
index bcfad85c42..65abf6ca90 100644
--- a/src/Query/Parser.php
+++ b/src/Query/Parser.php
@@ -5,7 +5,6 @@
 namespace Doctrine\ORM\Query;
 
 use Doctrine\Common\Lexer\Token;
-use Doctrine\Deprecations\Deprecation;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Exception\DuplicateFieldException;
 use Doctrine\ORM\Exception\NoMatchingPropertyException;
@@ -13,7 +12,6 @@
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Query;
 use Doctrine\ORM\Query\AST\Functions;
-use Doctrine\ORM\Query\Exec\SqlFinalizer;
 use LogicException;
 use ReflectionClass;
 
@@ -158,7 +156,7 @@ final class Parser
     /**
      * The custom last tree walker, if any, that is responsible for producing the output.
      *
-     * @var class-string<SqlWalker>|null
+     * @var class-string<OutputWalker>|null
      */
     private $customOutputWalker;
 
@@ -177,24 +175,6 @@ public function __construct(private readonly Query $query)
         $this->parserResult = new ParserResult();
     }
 
-    /**
-     * Sets a custom tree walker that produces output.
-     * This tree walker will be run last over the AST, after any other walkers.
-     *
-     * @param class-string<SqlWalker> $className
-     */
-    public function setCustomOutputTreeWalker(string $className): void
-    {
-        Deprecation::trigger(
-            'doctrine/orm',
-            'https://github.com/doctrine/orm/pull/11641',
-            '%s is deprecated, set the output walker class with the \Doctrine\ORM\Query::HINT_CUSTOM_OUTPUT_WALKER query hint instead',
-            __METHOD__,
-        );
-
-        $this->customOutputWalker = $className;
-    }
-
     /**
      * Adds a custom tree walker for modifying the AST.
      *
@@ -359,23 +339,7 @@ public function parse(): ParserResult
         $outputWalkerClass = $this->customOutputWalker ?: SqlOutputWalker::class;
         $outputWalker      = new $outputWalkerClass($this->query, $this->parserResult, $this->queryComponents);
 
-        if ($outputWalker instanceof OutputWalker) {
-            $finalizer = $outputWalker->getFinalizer($AST);
-            $this->parserResult->setSqlFinalizer($finalizer);
-        } else {
-            Deprecation::trigger(
-                'doctrine/orm',
-                'https://github.com/doctrine/orm/pull/11188/',
-                'Your output walker class %s should implement %s in order to provide a %s. This also means the output walker should not use the query firstResult/maxResult values, which should be read from the query by the SqlFinalizer only.',
-                $outputWalkerClass,
-                OutputWalker::class,
-                SqlFinalizer::class,
-            );
-            // @phpstan-ignore method.deprecated
-            $executor = $outputWalker->getExecutor($AST);
-            // @phpstan-ignore method.deprecated
-            $this->parserResult->setSqlExecutor($executor);
-        }
+        $this->parserResult->setSqlFinalizer($outputWalker->getFinalizer($AST));
 
         return $this->parserResult;
     }
diff --git a/src/Query/SqlWalker.php b/src/Query/SqlWalker.php
index 8164ae13bb..c8797e736b 100644
--- a/src/Query/SqlWalker.php
+++ b/src/Query/SqlWalker.php
@@ -230,22 +230,6 @@ public function setQueryComponent(string $dqlAlias, array $queryComponent): void
         $this->queryComponents[$dqlAlias] = $queryComponent;
     }
 
-    /**
-     * Gets an executor that can be used to execute the result of this walker.
-     *
-     * @deprecated Output walkers should no longer create the executor directly, but instead provide
-     *             a SqlFinalizer by implementing the `OutputWalker` interface. Thus, this method is
-     *             no longer needed and will be removed in 4.0.
-     */
-    public function getExecutor(AST\SelectStatement|AST\UpdateStatement|AST\DeleteStatement $statement): Exec\AbstractSqlExecutor
-    {
-        return match (true) {
-            $statement instanceof AST\UpdateStatement => $this->createUpdateStatementExecutor($statement),
-            $statement instanceof AST\DeleteStatement => $this->createDeleteStatementExecutor($statement),
-            default => new Exec\SingleSelectExecutor($statement, $this),
-        };
-    }
-
     /** @psalm-internal Doctrine\ORM */
     protected function createUpdateStatementExecutor(AST\UpdateStatement $AST): Exec\AbstractSqlExecutor
     {
diff --git a/tests/Tests/ORM/Functional/PaginationTest.php b/tests/Tests/ORM/Functional/PaginationTest.php
index db89c353d4..66cc3f9a9b 100644
--- a/tests/Tests/ORM/Functional/PaginationTest.php
+++ b/tests/Tests/ORM/Functional/PaginationTest.php
@@ -12,6 +12,7 @@
 use Doctrine\ORM\Query\AST\PathExpression;
 use Doctrine\ORM\Query\AST\SelectStatement;
 use Doctrine\ORM\Query\AST\WhereClause;
+use Doctrine\ORM\Query\SqlOutputWalker;
 use Doctrine\ORM\Query\SqlWalker;
 use Doctrine\ORM\Query\TreeWalkerAdapter;
 use Doctrine\ORM\Tools\Pagination\Paginator;
@@ -643,7 +644,7 @@ public function testCountQueryStripsParametersInSelect(): void
         self::assertCount(2, $getCountQuery->invoke($paginator)->getParameters());
         self::assertCount(9, $paginator);
 
-        $query->setHint(Query::HINT_CUSTOM_OUTPUT_WALKER, SqlWalker::class);
+        $query->setHint(Query::HINT_CUSTOM_OUTPUT_WALKER, SqlOutputWalker::class);
 
         $paginator = new Paginator($query);
 
diff --git a/tests/Tests/ORM/Functional/ParserResultSerializationTest.php b/tests/Tests/ORM/Functional/ParserResultSerializationTest.php
index 6918bd8e50..f673f5ebd9 100644
--- a/tests/Tests/ORM/Functional/ParserResultSerializationTest.php
+++ b/tests/Tests/ORM/Functional/ParserResultSerializationTest.php
@@ -32,25 +32,6 @@ protected function setUp(): void
         parent::setUp();
     }
 
-    /** @param Closure(ParserResult): ParserResult $toSerializedAndBack */
-    #[DataProvider('provideToSerializedAndBack')]
-    public function testSerializeParserResultForQueryWithSqlWalker(Closure $toSerializedAndBack): void
-    {
-        $query = $this->_em
-            ->createQuery('SELECT u FROM Doctrine\Tests\Models\Company\CompanyEmployee u WHERE u.name = :name');
-
-        // Use the (legacy) SqlWalker which directly puts an SqlExecutor instance into the parser result
-        $query->setHint(Query::HINT_CUSTOM_OUTPUT_WALKER, Query\SqlWalker::class);
-
-        $parserResult = self::parseQuery($query);
-        $unserialized = $toSerializedAndBack($parserResult);
-
-        $this->assertInstanceOf(ParserResult::class, $unserialized);
-        $this->assertInstanceOf(ResultSetMapping::class, $unserialized->getResultSetMapping());
-        $this->assertEquals(['name' => [0]], $unserialized->getParameterMappings());
-        $this->assertNotNull($unserialized->prepareSqlExecutor($query));
-    }
-
     /** @param Closure(ParserResult): ParserResult $toSerializedAndBack */
     #[DataProvider('provideToSerializedAndBack')]
     public function testSerializeParserResultForQueryWithSqlOutputWalker(Closure $toSerializedAndBack): void