diff --git a/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php b/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
index a900cad025e..bc9ce694be0 100644
--- a/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
@@ -2670,6 +2670,12 @@ public function getColumnCollationDeclarationSQL($collation)
      */
     public function prefersSequences()
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::prefersSequences() is deprecated without replacement and removed in DBAL 3.0'
+        );
+
         return false;
     }
 
@@ -3241,6 +3247,12 @@ public function supportsForeignKeyConstraints()
      */
     public function supportsForeignKeyOnUpdate()
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::supportsForeignKeyOnUpdate() is deprecated without replacement and removed in DBAL 3.0'
+        );
+
         return $this->supportsForeignKeyConstraints();
     }
 
@@ -3496,6 +3508,13 @@ public function supportsLimitOffset()
      */
     public function getSQLResultCasing($column)
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::getSQLResultCasing is deprecated without replacement and removed in DBAL 3.' .
+            'Use Portability\Connection with PORTABILITY_FIX_CASE to get portable result cases.'
+        );
+
         return $column;
     }
 
diff --git a/lib/Doctrine/DBAL/Platforms/OraclePlatform.php b/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
index bfb6270c1c4..88b4325b7ce 100644
--- a/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
@@ -974,6 +974,12 @@ protected function getRenameIndexSQL($oldIndexName, Index $index, $tableName)
      */
     public function prefersSequences()
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::prefersSequences() is deprecated without replacement and removed in DBAL 3.0'
+        );
+
         return true;
     }
 
@@ -1142,6 +1148,12 @@ public function supportsSequences()
      */
     public function supportsForeignKeyOnUpdate()
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::supportsForeignKeyOnUpdate() is deprecated without replacement and removed in DBAL 3.0'
+        );
+
         return false;
     }
 
diff --git a/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php b/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
index 9c1121cd985..3503d54d51f 100644
--- a/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
@@ -14,6 +14,7 @@
 use Doctrine\DBAL\Types\BlobType;
 use Doctrine\DBAL\Types\IntegerType;
 use Doctrine\DBAL\Types\Type;
+use Doctrine\Deprecations\Deprecation;
 use UnexpectedValueException;
 
 use function array_diff;
@@ -215,6 +216,12 @@ public function supportsCommentOnStatement()
      */
     public function prefersSequences()
     {
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pull/4229',
+            'AbstractPlatform::prefersSequences() is deprecated without replacement and removed in DBAL 3.0'
+        );
+
         return true;
     }