addmaths07 0 Newbie Poster

Hey! I am developing a type of an rss reader. Which fetches latest 1-2 feeds from a webserver and publishes them to a subscriber.
The problem I am facing is, this feedparser is using etag and modified date to recognise latest feeds. It works fine with the servers which support either one of these, but how to recognise feeds with no etag and modified date? I mean, I am not able to differentiate and get new 1-2 feeds from all the enties.
There must be known way of doing this because this Parser is very popular. Can anyone here help me out? I am quite new at this.