If you open Mobile Locker and see this alert, you'll know there's a new version available.
We always recommend updating to the latest version.
Open Safari on your iPad/iPhone and go to http://appstore.com/mobilelocker or search for Mobile Locker in the App Store like this:
Tap the UPDATE button.
Once the update is done, close the App Store and open Mobile Locker. This is what the new icon looks like: