MODE 14 is not directly selectable on recent 878 firmware versions, you first need to enter a password to enable this band. When MODE and the band number is displayed, press any number on the keypad and the radio will ask "INPUT PASSWORD:" Enter 878* as the password, and then you should be able to select MODE 00014.
This password has changed very slightly in v1.16, you should be able to work out what the new password is.