version

version is a string that represents the format of the subscription list. It always exists, although it may be an empty string if the subscription list format is not recognized.

These are the possible values:

opml1

OPML 1.0 and 1.1 [1]

opml2

OPML version 2.0

opml

An OPML file with an unknown or unspecified version

rdf

RDF+FOAF

igoogle

iGoogle exported settings format [2]

Footnotes

[1]	OPML 1.1 files are treated as OPML 1.0 files.

[2]	How to export your iGoogle page settings