My Galaxy Ace is 1 month old and on the Tesco mobile network. I have recieved an alert notified by a green cross in the top left corner of the screen. When opened it reads Your battery needs an update. Tap here. This is my first android phone and I am wary of trusting such messages. If I were on my computer and would delete any message from an unknown source, but I don't know with this. Advice Please.