will it still work as a midi controller? If so, how?
It depends on your operating system. If you're on Windows you'll always be able to use the MK1 keyboard, with Komplete Kontrol 2.9.6 or in MIDI mode. To edit the MIDI assignments you'll have to do it with Controller Editor. It will also always work as a MIDI controller when using a 5din MIDI cable.
More information here: Notes on Ending Software Support for Komplete Kontrol S-Series MK1 Keyboards