diff --git a/UPGRADE.md b/UPGRADE.md
index 15f11853f02..a5d7a66169e 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,5 +1,10 @@
 # Upgrade to 2.11
 
+## Deprecated `MasterSlaveConnection`
+
+The naming is offensive, the implementation very questionable. Use regular
+connections and switch between them explicitely.
+
 ## Deprecated `FetchMode` and the corresponding methods
 
 1. The `FetchMode` class and the `setFetchMode()` method of the `Connection` and `Statement` interfaces are deprecated.
diff --git a/lib/Doctrine/DBAL/Connections/MasterSlaveConnection.php b/lib/Doctrine/DBAL/Connections/MasterSlaveConnection.php
index 9362bc0c636..032c74672dc 100644
--- a/lib/Doctrine/DBAL/Connections/MasterSlaveConnection.php
+++ b/lib/Doctrine/DBAL/Connections/MasterSlaveConnection.php
@@ -15,6 +15,10 @@
 use function assert;
 use function count;
 use function func_get_args;
+use function sprintf;
+use function trigger_error;
+
+use const E_USER_DEPRECATED;
 
 /**
  * Master-Slave Connection
@@ -53,6 +57,8 @@
  *
  * Instantiation through the DriverManager looks like:
  *
+ * @deprecated use regular connections instead
+ *
  * @example
  *
  * $conn = DriverManager::getConnection(array(
@@ -93,6 +99,11 @@ class MasterSlaveConnection extends Connection
      */
     public function __construct(array $params, Driver $driver, ?Configuration $config = null, ?EventManager $eventManager = null)
     {
+        @trigger_error(sprintf(
+            'Class "%s" is deprecated since doctrine/dbal 2.11 and will be removed in 3.0',
+            self::class,
+        ), E_USER_DEPRECATED);
+
         if (! isset($params['slaves'], $params['master'])) {
             throw new InvalidArgumentException('master or slaves configuration missing');
         }