King had threatened legal action after the Robins claimed they could no longer afford payments as part of his contract severance.
But an agreement has now been reached, with deputy chairman Mark Devlin saying: "I very much regret the amount of time it has taken the club to sort out this matter.
"But I'm pleased a mutually acceptable agreement has been reached and all parties can now move on. We'd like to wish Andy all the very best for the future."