Thankfully, according to Dantz co-founder: Retrospect's demise greatly exaggerated, the Retrospect backup software is still alive.

I have to admit, I have been worried. I've been an enthusiastic Retrospect user for over 13 years now, as it's one of the few networked backup solutions for Macs, and a few years ago was cross platform. There are plenty of solutions that back up Macs, but very few that allow the backup server to be a Mac. If you're a Mac only shop, Retrospect will probably be the application you choose.