From the schema
Top-level list of one or more IATI activity records.
|@version||A number indicating the IATI specification version in use.|
|@generated-datetime||A date/time stamp for when this file was generated. This is not necessarily the last-updated date for the individual activity records in it. Uses ISO 8601 date format, e.g. "2010-03-12T18:45:00+01:00". Use of this attribute is highly recommended, to allow recipients to know when a file has been updated.|
Example that uses version 1.01, and was generated on 29th May 2012:
<iati-activities version="1.01" generated-datetime="2012-05-29T00:00:00"> .... </iati-activities>