Add to that the following (mildly edited) warning from one university's IT services:
Information and Communications Technology (ICT) strongly recommends postponing the upgrade of Apple iPhones and iPads to iOS 7 [+ 7.0.1].
Many devices upgraded in the past two days no longer sync with our email system, leaving them unable to send or receive email. ICT is investigating this issue and will post a follow-up message when it has been resolved or a work-around is available.
Even once resolved, ICT recommends a cautious approach to the iOS 7 upgrade. Waiting for several days or weeks increases the likelihood that minor bugs will have been addressed and that important applications will have been updated to work with the new operating system.
If your device has already been updated and you are experiencing problems syncing your email, ICT recommends using Safari on your device and logging into [the campus website] to access email in the interim.