I'm not sure about up-to-date specs per se. Nothing published about any advancements on the protocol in recent times that the gnutella forums has become aware of.

For older reference there's https://www.gnutellaforums.com/gener...tml#post378953

Posted the details I saved from any now defunct web links in arne_bab's post (those I was able to find.)

I suspect this is still the method you should be using now. Nothing dramatic has changed since. If it has it's probably in GTK-Gnutella's area.