For anyone wanting to do this (update currently at 1.62.3) I have figured out a method.
First of all, make sure you backup your current configuration!
Go to :-
And in the right corner you will see the “Package actions” box, click “download from mirror”. This will download the :-
libretro-snes9x-2390-1-x86_64.pkg.tar.zst file (636kb).
Now, extract this file into a new folder (I used RAR from RarLab in the PlayStore but I imagine any prog/app that supports tar files extraction will work). Inside the folder should be a “usr” folder and inside there will be two more folders. In the “lib” folder will be “libretro” and in here will be the :-
Copy this file into the appropriate libretro cores folder. Mine is :-
(I made a core backup and put this in a separate folder along with a direct copy of the core file. I then deleted the original).
Now restart Batocera and if you have done everything correctly Retroarch will automatically use the new version of the Snes9x core. In the “information” tab it will be displayed as Snes9x_current but it will also show that it’s the new version.