My RSS feed not updating in all readers

[RRJJMM]

Rather than relying on a feed "builder" I decided to learn some xml and write my own code for an RSS feed. Unfortunetly, the feed does not update properly in some readers. In particular, udates don't show up in Thunderbird.

I give every item a guid. (I use <guid isPermaLink="false"> with a code number).
I give every item a pubDate date/time in GMT.
When I update I give "channel" a new "last build date" in GMT.

Is there some trigger that I have missed that the reader is looking for to let it know that there is a new item out there?

I have read that some T-bird users have troubles with some feeds not updating and they have a work around of sorts (didn't work too well for me). If possible, however, I would like to fix things on my end rather than have my clients go out and find a work around for my poor coding.

Thanks,

[xav0989]

There is probably a problem with the cache of some feed reader.

[techfun]

Feed readers cache only latest feeds in some case.

[RRJJMM]

Thanks for the feedback. Maybe there is nothing I can do on my end to fix things. I'll just have to hope for bug fixes in the reader.