Parallels sent out an email today notifying users that their Parallels 7 software will no longer work with the OS X 10.9 update. Of course there will be no free update for existing users, but they did suggest that you rush on over and buy their Parallels 9 software, which is the only version that will work with Mavericks.
Here’s the upgrade link if anyone is interested (note: we’re not affiliated with Parallels or paid by them in any way). The upgrade will run you $49.99 and it looks like right now they are throwing in a free 6 month subscription to Parallels Access for iPads (normally $39.99). Although it would be nice to get a discounted upgrade for the OS X 10.9 release, it doesn’t exactly fit their business model. In any case, be sure to backup and finish everything on your virtual machine before updating your Apple gear as you won’t be able to access it if you upgrade OS X!