diff --git a/Documentation/Books/Users/Upgrading/UpgradingChanges23.mdpp b/Documentation/Books/Users/Upgrading/UpgradingChanges23.mdpp
index c2ea30ad6c..2c5d844adc 100644
--- a/Documentation/Books/Users/Upgrading/UpgradingChanges23.mdpp
+++ b/Documentation/Books/Users/Upgrading/UpgradingChanges23.mdpp
@@ -105,6 +105,14 @@ Here is a summary of changes:
   receive invalid arguments will then return `null`.
 
 
+!SUBSECTION Nested FOR loop execution order
+
+The query optimizer in 2.3 may permute the order of nested `FOR` loops in AQL queries,
+provided that exchanging the loops will not alter a query result. However, a change
+in the order of returned values is allowed because no sort order is guaranteed by AQL
+(and was never) unless an explicit `SORT` statement is used in a query.
+
+
 !SUBSECTION Changed return values of ArangoQueryCursor.getExtra()
 
 The return value of `ArangoQueryCursor.getExtra()` has been changed in ArangoDB 2.3.