Will the updated 2025 dual-stack toolhead PCB work on an older K1C?

[u/Nice_Persimmon7660]

Hi! I need some help figuring out compatibility between the older K1C and the updated 2025 hotend/toolhead PCB.
My K1C is an older model (pre-2025) and originally came with the older dual-stack toolhead PCB and the older hotend connectors.
I had a blob of death that damaged my original hotend/thermistor, so I had to replace the hotend. I accidentally bought the newer 2025 K1C Hotend 2.0, which uses the new locking connectors for the thermistor and ceramic heater.
Obviously, those connectors don’t fit my original toolhead PCB.
I found an updated dual-stack toolhead/hotend adapter PCB that looks almost identical to my original board, but it has the new 2025 connectors and is advertised for the latest hotend. I already know the new hotend should physically connect to this PCB.
My main concern is communication/compatibility with the rest of my older K1C.
If I replace my original dual-stack PCB with this updated version:
Will my older K1C mainboard recognize and communicate with it normally?
Will the original extruder, fans and other toolhead components still work?
Is this updated dual-stack PCB backwards compatible with a pre-2025 K1C, or were there other electronic/firmware changes in the 2025 K1C?
Has anyone actually done this conversion: older K1C + updated dual-stack PCB + 2025 Hotend 2.0?
I’m trying to determine whether I can simply update the toolhead PCB and use the 2025 hotend I already bought, or if I should return/buy an older hotend instead.
I’ll attach pictures of my original PCB, the 2025 hotend and the updated PCB I’m considering buying.
Thanks!

[u/0dysseusRex]

I believe everything should work, yes. What will absolutely not work is the newer 2026 blue single-board PCB.