The static updates file holds all of the series updates on the given day. By calling /api/<apikey>/updates/yyyy-mm-dd.xml you can retrieve all of the updates for any day, starting with January 28, 2008 (the start date for the new API). You can also leave off the yyyy-mm-dd.xml portion and it will return the current day's file.
This file currently holds two types of records. The first is the <Time> record, which gives the local timestamp of the file. The second is the <Series> record, which will list all of the series that have been updated on this date.
<?xml version="1.0" encoding="UTF-8" ?> <Updates> <Time>1201575151</Time> <series>80348</series> </Updates>