diff --git a/UPGRADE.md b/UPGRADE.md
index 0c1fba1e138..af2bc574ffc 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -16,6 +16,10 @@ Use `AbstractSchemaManager::listSchemaNames()` instead.
 
 `PostgreSQLSchemaManager::getExistingSchemaSearchPaths()` and `::determineExistingSchemaSearchPaths()` have been marked internal.
 
+## `OracleSchemaManager` methods marked internal.
+
+`OracleSchemaManager::dropAutoincrement()` has been marked internal.
+
 ## Deprecated `AbstractPlatform::getReservedKeywordsClass()`
 
 Instead of implementing `getReservedKeywordsClass()`, `AbstractPlatform` subclasses should implement
diff --git a/src/Schema/OracleSchemaManager.php b/src/Schema/OracleSchemaManager.php
index 078c95fc2a4..0c89d6855d7 100644
--- a/src/Schema/OracleSchemaManager.php
+++ b/src/Schema/OracleSchemaManager.php
@@ -264,6 +264,8 @@ public function createDatabase($database)
     }
 
     /**
+     * @internal The method should be only used from within the OracleSchemaManager class hierarchy.
+     *
      * @param string $table
      *
      * @return bool