Lifetimes of Open Source Projects

So I tried contributing a new feature to an open source project whose last release was in 2009. I didn’t know how many developers still monitored the mailing list, but I thought I would at least get a response to my emailed patch. It’s hosted on SourceForge, so I figured it probably wasn’t under active development. I don’t think my email even got through moderation, I subscribed to the mailing list before sending a message, but it seems to have binned me as Post by non-member to a members-only list.