Amusing, considering I was bashed last night with repeated "you can't patch it once it's on Mars".
But the software, as far as I know, is very modular, so this could be only an upgrade of some modules
Edit: by RTFA this looks more like a replacement rather than an update, like, making usage of all the landing software space since this is not needed anymore.
(I was working on the Rover team at the time)