Hey there, we've been testing with iOS 11 and find no issues. However, we haven't had a lot of reports yet. If you've got a gig this weekend, don't upgrade until after. Then once you upgrade, hit us up at support [at] mididesigner.com with any issues. If it's an issue we can replicate (most are), then we can fix it and get you a beta build VERY quickly.
Thanks!
Dan