diff --git a/db/zm_update-1.34.20.sql b/db/zm_update-1.34.20.sql
new file mode 100644
index 000000000..3512534be
--- /dev/null
+++ b/db/zm_update-1.34.20.sql
@@ -0,0 +1,2 @@
+/* This was done in 1.31.0 but zm_create.sql.in wasn't updated to match. */
+ALTER TABLE Monitors MODIFY LinkedMonitors varchar(255);