Kevin's mobile phone needs to be updated, but he can't because there's not enough room. Leo says that Kevin's phone probably has too little storage. He may need to wipe the phone and restore it to factory default settings, and then try updating it. Kevin should backup his data first and then give that a try. If that doesn't work, there's simply not enough room for the latest update and he's out of luck. The extra benefit of wiping and reinstalling is that it will clear out any bad popups or kruft left behind by old apps.
Kevin should check out this page at support.google.com found by ScooterX in the chatroom.