[Ubuntu] New /boot/grub/menu.lst after `apt-get upgrade`?

Hi there!

Just started a new droplet with Docker.

I wanted to make sure I have the newest version, so I ran apt-get update and apt-get upgrade after which I got the following in Terminal:

A new version of /boot/grub/menu.lst is available, but the version
     │ installed currently has been locally modified.
 
     │ What would you like to do about menu.lst?
 
     │      install the package maintainer's version
     │      keep the local version currently installed
     │      show the differences between the versions
     │      show a side-by-side difference between the versions
     │      show a 3-way difference between available versions
     │      do a 3-way merge between available versions (experimental)   
     │      start a new shell to examine the situation

I’ve never edited the menu.lst file, I imagine this is something done by DO.

What exactly is happening here, and what option should I select?

Thanks!

Dillon