I had 4988 stepper drivers on a K8200.
Now DRV8825 and they work but best buy pololu DRV8825 cause there are china clones that will destroy steppers if not to be careful.
And if the stepper boards are placed in-line, yoiu may expect one stepper driver that will not fit so good due to board size deviations with the chinese models.
ok, the polulu is also made in China.
General rule is:
Products made in China with western companies that create the schematics , the pcb layout and component placement and keep an western eye on the production: ok
Made in China en tested by the same Chinese company: avoid that.
Be aware to use cooling on these DRV’s
So conclusion is:
If on the mainboard of the K8400 fits DRV8825, then 4988 wxill work too.
But keep an eye on the firmware: 4988 uses 1/16 microstep , 8825 1/32