diff --git a/doc/src/sgml/ref/declare.sgml b/doc/src/sgml/ref/declare.sgml
index 5cb85cc568..864c3d75f7 100644
--- a/doc/src/sgml/ref/declare.sgml
+++ b/doc/src/sgml/ref/declare.sgml
@@ -271,7 +271,8 @@ DECLARE name [ BINARY ] [ INSENSITI
and not use grouping or ORDER BY>). Cursors
that are not simply updatable might work, or might not, depending on plan
choice details; so in the worst case, an application might work in testing
- and then fail in production.
+ and then fail in production. If FOR UPDATE is
+ specified, the cursor is guaranteed to be updatable.