The defending champions were West Bromwich Albion, who defeated Wolverhampton Wanderers on penalties in the previous final.
[1] This season saw the return of a Under-21 age limit, reduced from Under-23 the previous season, with clubs permitted to use five over-age outfield players and an over-age goalkeeper in order to help with the transition.
Mansfield Town, Salford City, and Stevenage did not return from last years competition only playing once, Oxford United, Plymouth Argyle, West Ham United, Wigan Athletic left after 3, 3, 2, and 2 consecutive seasons respectively, Southend United did not return after 6 straight seasons in the competition, Norwich City didn't return after playing last year, and Exeter City and Leeds United did not return after 4 consecutive seasons in the competition.
[3] Teams play each other twice, with the group winners and runners–up advance to the round of 16.
[34] Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.