I got the little red 'number one' notification ,which when pressed gave the option of the update.
Forewarned by this thread I just pressed the 'decline' button.
I have never used the built in version anyway. And never likely to. ( I got a printed version which I carry in the car. )
I mostly use the on- line pdf version which has more information and is searchable. I will make sure I have downloaded the latest version of this in case there are any significant changes. Its time I read it again anyway. I can then claim the things I never knew , or already forgotten ,must be new updates.