Since Mac OS X Server 10.4, apple has included a software update service that allows you to mirror their software updates to your local server, and configure your clients to check the local server for updates instead of the Apple servers. This has a few benefits — it can save you a lot of bandwidth when updating lots of clients, you can choose which updates are pushed to your clients and when, and so on. However, when a new major release of Mac OS X comes along, like this past August’s release of Mac OS X 10.6, they want you to upgrade your server OS to the new release for their software update service to grab the updates for the new client OS.
In other words, if you have a server running Mac OS X Server 10.5, you can’t use it to serve updates to client machines running Mac OS X 10.6, unless you upgrade the server to 10.6 as well. This limitation seems a little silly, surely Apple could push an update for Mac OS X Server 10.5 that told it where to look for 10.6 updates. The update service itself doesn’t seem to have really changed — you can tell your 10.6 clients to check your 10.5 server for updates, and it will work fine, you’ll just miss out on updates specific to Mac OS X 10.6.
…or is there a way around this limitation?