Don't think its used in the Carabao cup until the final - or possibly semi-finals if BOTH venues have it installed
Cheers mate but I thought every ground that has it used it, they did at Burnley in the F.A. Cup a few years back. I know it's a different competition, I hope you're right.
EFL take a different approach to FA, I think all venues in each round have to have it for it to be used