diff --git a/UPGRADE.md b/UPGRADE.md
index 26b0058b577..5dc30b6db27 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,5 +1,9 @@
 # Upgrade to 3.0
 
+## Removed `Portability\Connection::PORTABILITY_{PLATFORM}` constants`
+
+The platform-specific portability constants were internal implementation details which are longer relevant.
+
 ## BC BREAK changes in fetching statement results
 
 1. The `Statement` interface no longer extends `ResultStatement`.
diff --git a/src/Portability/Connection.php b/src/Portability/Connection.php
index 4200b28853a..3886a58ce99 100644
--- a/src/Portability/Connection.php
+++ b/src/Portability/Connection.php
@@ -25,19 +25,6 @@ class Connection extends \Doctrine\DBAL\Connection
     public const PORTABILITY_EMPTY_TO_NULL = 4;
     public const PORTABILITY_FIX_CASE      = 8;
 
-    /**#@+
-     *
-     * @deprecated Will be removed as internal implementation details.
-     */
-    public const PORTABILITY_DB2          = 13;
-    public const PORTABILITY_ORACLE       = 9;
-    public const PORTABILITY_POSTGRESQL   = 13;
-    public const PORTABILITY_SQLITE       = 13;
-    public const PORTABILITY_OTHERVENDORS = 12;
-    public const PORTABILITY_SQLANYWHERE  = 13;
-    public const PORTABILITY_SQLSRV       = 13;
-    /**#@-*/
-
     /** @var Converter */
     private $converter;