We have identified a critical bug in previous release (version 11.7) that went public on 22-Nov-2016. This bug caused a small percentage of the users to lose notes taken on that day.
We have submitted an emergency release to Apple immediately and it is currently live on the App Store as of 23-Nov-2016. Please update to the latest version 11.8 of Noteshelf before using the app.
Our deepest apologize for those who were effected by this issued. We are taking every measure to prevent this kind of occurrence to happen in future. Please be assured that we are committed to providing the best experience for our users.