There is an upgrade kit for the Prusa Mk2 that can be installed by anyone who wishes to take this on.
This upgrade adds a magnetic sheet print bed like the Mk3 has, as well as the latest extruder assembly. The extruder assembly is the same as the Mk3S. There is "filament out" detection that will pause a print when the filament runs out for a quick change and print resume. I have a Mk3S at home and the performance and reliability is fantastic.
Most importantly this upgrade will remove the MMU (Multi Material Um,something) that has been unreliable and problematic since the day it was installed.
The kit has everything needed and all the printed parts required I've already printed in PETG.
The main difference between the Mk2.5S and Mk3S is the operating voltage, the Mk2's are 12 volt and all the Mk3's are 24 volt, which really isn't an upgrade worth making on its own.
I've donated this kit to the space in the hopes that someone can use it as the Prusa Printers are typically phenomenal machines but the MMU1 is a lemon.
The upgrade kit instructions can be found here: Mk2S to MK2.5S Instructions
The MMU1 upgrade instructions might also be helpful for disassembly. MMU1 installation.
Official Prusa Webstore Upgrade Kit link.