I have app in App Store, I submitted version 1.1, after Apple reviewed, approved and published it, I noticed there is a clear major bug, so I had to suspend my app from App Stor
So, It is quite clear that we can't revert to the previous version on the App Store and the only solution is to submit a new version to the store. But We can fasten up the reviewing process by requesting the Expedited reviews. please go to the link(Expedited Review Form) and Fill up the form.