diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index c76c1720919..d7d768c34fa 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -1,7 +1,7 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
-=== 4.0 ===
+=== 3.11 ===
 * New optional parameter $extracontent for print_collapsible_region_start(). This allows developers to add interactive HTML elements
   (e.g. a help icon) after the collapsible region's toggle link.