We are using MunkiServer 0.6 (just did a git pull a day or so ago, actually) and Munki 0.9.0.1797, with our Mac OS X 10.8.x clients. So far, I haven't noticed any issues as we use this combination in production. However, as I look forward to planning for a possible Mavericks deployment, I'm also considering a push of a newer version of the Munki tools.
My question: how aggressively can I keep up with Munki updates when used in conjunction with MunkiServer? Should I expect issues if I deploy a version too new to work with MunkiServer? I'm thinking that the answer is: "no, however MunkiServer may not have built-in support for some of the newer functionality of Munki" but I wanted to be sure.