Logstash-input-rss undefined method author

I am using logstash 2.3.4 with the rss plugin.
My config file is as follows:

input {
rss {
interval => 600
url => "http://advances.sciencemag.org/rss/current.xml"

When I start logstash, I get the following error message:
Plugin: <LogStash::Inputs::Rss interval=>600, url=>"http://advances.sciencemag.org/rss/current.xml", codec=><LogStash::Codecs::Plain charset=>"UTF-8">>
Error: undefined method `author' for #RSS::RDF::Item:0x7e227c79 {:level=>:error}

Is this something that can be fixed in the plugin, or is there some additional
configuration I need to add?

There was a recent commit (below) that fixed a problem where it was assumed that posts had authors, but AFAICT that was only for Atom feeds and this feed doesn't look like an Atom field. Which version of the rss plugin are you using?

Using the logstash list --verbose command,
it says that I am using logstash-input-rss(2.0.5). If this is not the latest version,
I will try my rss feed again with the latest update. Thank you very much for the feedback!

I have a question. when I run the the command to update the plugin
logstash-plugin update logstash-input-rss

I am asked if I would like to update to version 3.0.1, which I accept( respond Y).

But when I check the plugin version with this command (after running the update)
logstash-plugin list --verbose --group input it still says version 2.0.5.

Am I doing something wrong? I even removed it and installed it
completely again with logstash-plugin install logstash-input-rss which also gave version 2.0.5