Simplify the following text for a Grade 9 native English-speaking person.
Original: Despite the disappearance of the county , Middlesex is still used informally as an area name and was retained as a postal county ; which is now an optional component of postal addresses .
Simplified: Despite its disappearance as an administrative county , Middlesex is still used as an area name . It was kept as a postal county ; it is an optional component of postal addresses .