Thank you for the suggestions, but I had hoped for someone with successful, concrete experience who could point the way. Finding the precise older version that would work feels like searching for a needle in a haystack. Even if I could get it to run, then I would have to see if it supports Mavericks. I have looked at both websites (and others, too) before, but getting started is tough without knowing what will work and what will break. At some point it may be less time consuing and frustrating to buy a new or used Intel server and go from there.
Hopefully there is someone out there who is running a PowerPC Leopard or Leopard Server Mac, and can definitively say that they got CardDav and CalDav services running in a way that supports modern Macs, or simply that they tried it without success (and tell us what issues they ran into).
The Leopard Server supplied caldavd will work with for an iCal server, although it isn't flawless (however I'm not sure whether this is bad data or what). I haven't had time to figure out if I can get a version of carddav to work.
I am trying to update the caldavd in hopes of getting a combined caldavd/cardavd and also "fix" the caldavd bugs I've encountered, but haven't yet found how to put together a working set of Python on and server version.-kby
Just a follow up:
I tried setting up Baikal to run on a Leopard Server in a VMware guest as a trial effort. If it had worked, I would have installed it on the PowerPC Mac Mini and posted the details here. Unfortunately, I couldn't make it work, despite investing several hours. It required many deviations from the written procedure. In fairness, the procedure was written for a Mac running Mavericks.
After investing a reasonable amount of time and effort in an obsolete PowerPC Mac, I decided that it is time to retire it and replace it with a new Intel Mac Mini running Mavericks Server that can run local Contacts and Calendar sync services for the family Macs, iPhones, and iPads on the home network. I am still doing basic setup on the new Mac, and am not ready to tackle Contacts and Calendar syncing yet.
Here is one source for setting up Mavericks Server as a sync server. Note the comment describing a bug for Contacts syncing:
Here is another:
This thread is about getting a PowerPC Mac running Leopard (or Leopard Server) to do the job, so I won't hijack it for Intel/Mavericks issues. Thanks to all for their suggestions.