site feed does not validate

SpoonDrift的Feed始终无法通过W3C的 FEED Validation，每次都提示这样的错误：

This feed uses an obsolete namespace

<feed xmlns="http://purl.org/atom/ns#" version=" 0.3" xml:lang="en-US">

This feed is using an obsolete namespace used by an obsolete snapshot of Atom, which is not supported by this validator.

FEED Validation Service提供了解决这一问题的方法：

Blogger users with access to PHP can use these instructions.