Preserving edited settings.reader.lua (Android)

I'm trying out KOReader on Android to see if I want to switch to it for my devices (Android tablets, phones, and a Kindle Voyage (once jailbroken)).

I didn't like the white background for reading on my phone so I found this link which explains how to change the background color by adding to the settings.reader.lua file in the KOreader folder. Works fine and now I have a "parchment" color that's easier on eyes.

My question is: How can I preserve this change to persist through updates or will the settings.reader.lua file not be overwritten?