afaik the spam filters are not updated in any way.
there was a change in the spamassassin version from asl 4 (spamassassin 2.4.something) to asl 5 (spamassassin 2.6) and with that a change in the filters. the only spam filter change i saw in v4 was, when the smtp proxy did not recognise the new outlook2003 and marked all mails from this client as spam. it was more a bugfix than a filter change.
i saw the "AstaroSpamProtection"-Otion in my.astao.com but i talked to a sales person and he said its for future use.
correct me if i am wrong.
btw. a good feature would be an online spam database check like razor or dcc to increase the spamassassin score.....