Mikael Hansen wrote:

I was wondering if there is a way to automatically unsubscribe or
disable the membership for those who have not posted to a list for a
given period of time.

There is nothing direct in Mailman. You could make a file of addresses and post dates (or most recent post date) from Mailman's post log or maintain it on an ongoing basis from the post log, and then get a list of recent posters and use it as input to bin/sync_members, but do you really think this is a good idea?

Just the first problem that comes to mind is people that subscribe to both messages and digests with two different addresses and maybe only post from one.