diff --git a/src/bin/pg_dump/pg_upgrade b/src/bin/pg_dump/pg_upgrade
index e566a912ba6195e607f7b5e1235db49e9ffc35f2..6d54f84f5588719ee39b88a5c220bf76cb74ce0c 100755
--- a/src/bin/pg_dump/pg_upgrade
+++ b/src/bin/pg_dump/pg_upgrade
@@ -2,6 +2,9 @@
 #
 # pg_upgrade: update a database without needing a full dump/reload cycle
 # CAUTION: read the manual page before trying to use this!
+echo "pg_upgrade is disabled in this release because the on-disk structure" 1>&2
+echo "of the tables has changed compared to previous releases." 1>&2
+exit 1
 
 trap "rm -f /tmp/$$" 0 1 2 3 15