diff --git a/files/db/update_v3_to_v4.sql b/files/db/update_v3_to_v4.sql
index 093da8b..48b3e22 100644
--- a/files/db/update_v3_to_v4.sql
+++ b/files/db/update_v3_to_v4.sql
@@ -1,7 +1,7 @@
 ALTER TABLE messages ADD iso_time VARCHAR(24) AFTER longitude;
 ALTER TABLE messages CHANGE COLUMN timestamp site_time TIMESTAMP DEFAULT 0;
 ALTER TABLE messages CHANGE COLUMN unix_timestamp unix_time INT;
-UPDATE messages SET iso_time = CONCAT(REPLACE(CONVERT_TZ(FROM_UNIXTIME(unix_timestamp), @@session.time_zone, 'Pacific/Auckland'), ' ', 'T'), '+1200') WHERE id_feed = 1;
+UPDATE messages SET iso_time = CONCAT(REPLACE(CONVERT_TZ(FROM_UNIXTIME(unix_time), @@session.time_zone, 'Pacific/Auckland'), ' ', 'T'), '+1200') WHERE id_feed = 1;
 
 ALTER TABLE feeds MODIFY last_update TIMESTAMP DEFAULT 0;