Hmmmm, I just did a search for "Mk3DRV controller" and the first page I looked at is shown in this screenshot:
Page link: https://planet-cnc.com/product/mk3-drv/
And the last line in the "More details" section in the screenshot above says:
Seems clear enough . . .Controller requires license. Without license it is limited to 25 moves.
https://planet-cnc.com/product/mk3-drv/