I have seen a similar post from a couple of years ago but could not find an answer given.
I have a BT Freestyle 4100 base station with 4 handsets. They have been working great for the last 12+ years. A couple of days ago, on all 4 handsets the bottom line of the display disappeared (the line where the date & time show) and was replaced with a strange icon on the extreme right-hand side. As per the previous post mentioned it looks like an American-style mailbox.
I have read the manual, scrolled through all the menu options on the handset and extensively trawled the internet but have been unable to find the cause. The fact that it has appeared on all 4 handsets at the same time leads me to believe that it is something to do with the base station. I do not have any SMS or similar service on my landline phone so cannot see how it could be anything to do with this.
Any help with what has caused this and how I can get rid of the icon would be much appreciated.