YOU CAN'T UPGRADE DIRECTLY FROM MK2S MMU1 to MMU2S !!! You need to upgrade to MK2.5S first.
MK2S to MK2.5S upgrade is no longer being supported and sold as a kit. Please see this article about current upgrading options for MK2/S and MK2.5 printers.
⬢The upgrade process is the following:
⬢Disassemble your MK2S MMU1
⬢Prepare the MMU1 motors for MMU2S assembly
⬢Upgrade your printer to MK2.5S
⬢Upgrade your MK2.5S to MK2.5S MMU2S