diff --git a/UPGRADE.md b/UPGRADE.md
index bfc6101e783..90e306eadb4 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -666,6 +666,10 @@ Use `toIterable()` instead.
 
 # Upgrade to 2.17
 
+## Deprecate `Doctrine\ORM\Query\Exec\AbstractSqlExecutor::_sqlStatements`
+
+Use `Doctrine\ORM\Query\Exec\AbstractSqlExecutor::sqlStatements` instead.
+
 ## Undeprecate `Doctrine\ORM\Proxy\Autoloader`
 
 It will be a full-fledged class, no longer extending
@@ -675,16 +679,17 @@ It will be a full-fledged class, no longer extending
 
 When the `AUTO` identifier generation strategy was introduced, the best
 strategy at the time was selected for each database platform.
-A lot of time has passed since then, and support for better strategies has been
-added.
+A lot of time has passed since then, and with ORM 3.0.0 and DBAL 4.0.0, support
+for better strategies will be added.
 
 Because of that, it is now deprecated to rely on the historical defaults when
-they differ from what we recommend now.
+they differ from what we will be recommended in the future.
 
 Instead, you should pick a strategy for each database platform you use, and it
 will be used when using `AUTO`. As of now, only PostgreSQL is affected by this.
-It is recommended that PostgreSQL user configure their new applications to use
-`IDENTITY`:
+
+It is recommended that PostgreSQL users configure their existing and new
+applications to use `SEQUENCE` until `doctrine/dbal` 4.0.0 is released:
 
 ```php
 use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
@@ -692,12 +697,12 @@ use Doctrine\ORM\Configuration;
 
 assert($configuration instanceof Configuration);
 $configuration->setIdentityGenerationPreferences([
-    PostgreSQLPlatform::CLASS => ClassMetadata::GENERATOR_TYPE_IDENTITY,
+    PostgreSQLPlatform::CLASS => ClassMetadata::GENERATOR_TYPE_SEQUENCE,
 ]);
 ```
 
-If migrating an existing application is too costly, the deprecation can be
-addressed by configuring `SEQUENCE` as the default strategy.
+When DBAL 4 is released, `AUTO` will result in `IDENTITY`, and the above
+configuration should be removed to migrate to it.
 
 ## Deprecate `EntityManagerInterface::getPartialReference()`
 
diff --git a/docs/en/reference/basic-mapping.rst b/docs/en/reference/basic-mapping.rst
index 8c31983f721..9624b9fb4dd 100644
--- a/docs/en/reference/basic-mapping.rst
+++ b/docs/en/reference/basic-mapping.rst
@@ -330,7 +330,8 @@ vendor preferred at the time that strategy was introduced:
 ``AUTO_INCREMENT`` with MySQL, sequences with PostgreSQL and Oracle and
 so on.
 If you are using `doctrine/dbal` 4, we now recommend using ``IDENTITY``
-for PostgreSQL, and you can achieve that while still using the ``AUTO``
+for PostgreSQL, and ``AUTO`` resolves to it because of that.
+You can stick with ``SEQUENCE`` while still using the ``AUTO``
 strategy, by configuring what it defaults to.
 
 .. code-block:: php
@@ -341,7 +342,7 @@ strategy, by configuring what it defaults to.
 
     $config = new Configuration();
     $config->setIdentityGenerationPreferences([
-        PostgreSQLPlatform::class => ClassMetadata::GENERATOR_TYPE_IDENTITY,
+        PostgreSQLPlatform::class => ClassMetadata::GENERATOR_TYPE_SEQUENCE,
     ]);
 
 .. _identifier-generation-strategies:
diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
index dcddcf3194a..a368f85d788 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
@@ -7,6 +7,7 @@
 use Doctrine\Common\EventManager;
 use Doctrine\DBAL\Platforms;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
+use Doctrine\Deprecations\Deprecation;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Event\LoadClassMetadataEventArgs;
 use Doctrine\ORM\Event\OnClassMetadataNotFoundEventArgs;
@@ -626,6 +627,30 @@ private function determineIdGeneratorStrategy(AbstractPlatform $platform): int
 
         foreach ($nonIdentityDefaultStrategy as $platformFamily => $strategy) {
             if (is_a($platform, $platformFamily)) {
+                if ($platform instanceof Platforms\PostgreSQLPlatform) {
+                    Deprecation::trigger(
+                        'doctrine/orm',
+                        'https://github.com/doctrine/orm/issues/8893',
+                        <<<'DEPRECATION'
+                        Relying on non-optimal defaults for ID generation is deprecated, and IDENTITY
+                        results in SERIAL, which is not recommended.
+                        Instead, configure identifier generation strategies explicitly through
+                        configuration.
+                        We currently recommend "SEQUENCE" for "%s", when using DBAL 3,
+                        and "IDENTITY" when using DBAL 4,
+                        so you should use probably use the following configuration before upgrading to DBAL 4,
+                        and remove it after deploying that upgrade:
+
+                        $configuration->setIdentityGenerationPreferences([
+                            "%s" => ClassMetadata::GENERATOR_TYPE_SEQUENCE,
+                        ]);
+
+                        DEPRECATION,
+                        $platformFamily,
+                        $platformFamily,
+                    );
+                }
+
                 return $strategy;
             }
         }
diff --git a/tests/Doctrine/Tests/ORM/Functional/ParserResultSerializationTest.php b/tests/Doctrine/Tests/ORM/Functional/ParserResultSerializationTest.php
index 18cc692cbeb..bcf465faeb7 100644
--- a/tests/Doctrine/Tests/ORM/Functional/ParserResultSerializationTest.php
+++ b/tests/Doctrine/Tests/ORM/Functional/ParserResultSerializationTest.php
@@ -51,13 +51,13 @@ public function testUnserializeSingleSelectResult(string $serialized): void
         $this->assertInstanceOf(ResultSetMapping::class, $unserialized->getResultSetMapping());
         $this->assertEquals(['name' => [0]], $unserialized->getParameterMappings());
         $this->assertInstanceOf(SingleSelectExecutor::class, $unserialized->getSqlExecutor());
+        $this->assertIsString($unserialized->getSqlExecutor()->getSqlStatements());
     }
 
     /** @return Generator<string, array{string}> */
     public static function provideSerializedSingleSelectResults(): Generator
     {
-        yield '2.14.3' => [rtrim(file_get_contents(__DIR__ . '/ParserResults/single_select_2_14_3.txt'), "\n")];
-        yield '2.15.0' => [rtrim(file_get_contents(__DIR__ . '/ParserResults/single_select_2_15_0.txt'), "\n")];
+        yield '2.17.0' => [rtrim(file_get_contents(__DIR__ . '/ParserResults/single_select_2_17_0.txt'), "\n")];
     }
 
     private static function parseQuery(Query $query): ParserResult
diff --git a/tests/Doctrine/Tests/ORM/Functional/ParserResults/single_select_2_17_0.txt b/tests/Doctrine/Tests/ORM/Functional/ParserResults/single_select_2_17_0.txt
new file mode 100644
index 00000000000..aa854bfab92
Binary files /dev/null and b/tests/Doctrine/Tests/ORM/Functional/ParserResults/single_select_2_17_0.txt differ
diff --git a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
index 315dd203600..8dd886a6d9c 100644
--- a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
+++ b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
@@ -144,6 +144,22 @@ public function testPostgresSticksWithSequencesWhenDbal3IsUsed(): void
         self::assertSame(ClassMetadata::GENERATOR_TYPE_SEQUENCE, $metadata->generatorType);
     }
 
+    public function testRelyingOnLegacyIdGenerationDefaultsIsDeprecatedIfItResultsInADefaultThatWillChange(): void
+    {
+        if (! method_exists(AbstractPlatform::class, 'getIdentitySequenceName')) {
+            self::markTestSkipped('This test requires DBAL 3');
+        }
+
+        $cm = $this->createValidClassMetadata();
+        $cm->setIdGeneratorType(ClassMetadata::GENERATOR_TYPE_AUTO);
+        $cmf = $this->setUpCmfForPlatform(new PostgreSQLPlatform());
+        $cmf->setMetadataForClass($cm->name, $cm);
+
+        $metadata = $cmf->getMetadataFor($cm->name);
+
+        self::assertSame(ClassMetadata::GENERATOR_TYPE_SEQUENCE, $metadata->generatorType);
+    }
+
     public function testPostgresSwitchesToIdentityColumnsWhenDbal4IsUsed(): void
     {
         if (method_exists(AbstractPlatform::class, 'getIdentitySequenceName')) {