Prevent LockScreen notifications from being removed when unlocking your device or opening the Notification Center.
This is a lite version, with no extra options or settings to configure. It's basically as simple as a Flex tweak. It returns NO for "SBLockScreenNotificationListController removeItemsForUnlock" and "SBLockScreenNotificationListController removeItemsForNotificationCenterPresentation."
If you have Perpetual8 or Perpetual9 installed, you should remove or disable them.