MK Dons have learnt six of the seven new teams they will face in the 2021/22 season, following a dramatic final day in the Sky Bet Championship and Sky Bet League One.
Sheffield Wednesday, Rotherham United and Wycombe Wanderers were the three teams relegated from the second tier.
Wycombe beat Middlesbrough on the final day but drop out of the Championship along with Rotherham United, who were held to a draw by Cardiff City, and Sheffield Wednesday who played out a thrilling 3-3 draw with Derby County, who survived.
Meanwhile, in League Two, Cheltenham Town secured the League Two title and will be joined in the third tier by Cambridge United and Bolton Wanderers.
Cambridge, whose side included MK Dons loanee Hiram Boateng, ran out 3-0 winners over Grimsby Town while Bolton beat Crawley 4-1 to secure an immediate return back to League One.
The final new opponent will be confirmed later this month following the completion of the League Two Play-Offs.
Morecambe will face Tranmere Rovers for a place at Wembley, as will Newport County and Forest Green Rovers.
The Sky Bet League One will come to a close on Sunday lunchtime, with only the play-off places left to determine.
Hull City and Peterborough United have already sealed promotion to the Championship while Rochdale, Northampton Town, Swindon Town and Bristol Rovers have been relegated to League Two.
Blackpool, Sunderland and Lincoln City are already assured of a top-six finish, leaving Portsmouth, Oxford United and Charlton Athletic to battle it out for the final play-off spot on Sunday.
Confirmed Sky Bet League One teams in 2021/22: