Our users report some issues related to the use of MobileNoter on devices with iOS 4.x.
Some people complain that they are not asked for entering the passcode when they re-open the application with passcode lock option turned on. It happens because the latest update of MobileNoter supports multitasking feature of iOS 4. If the application is not closed completely, the user won't be asked for the passcode when he/she re-opens the app. To close the application you need to push the Home button twice, hold the icon until it starts to shake and tap on the red button with "-":

In the next update (version 2.2.1) this issue will be fixed and user will be asked for the passcode each time he/she returns to the application.
We'll also include some more bug fixes related to iOS 4.x in our update, including a fix to the problem with non-updating notebooks. We are sorry for inconvenince caused by this issue. We appreciate the patience of all our users.
UPDATE: We've located the cause of the problem with notebooks update (thanks to our beta-testers!). The fix will be available next week. Version number 2.2.1.