Kengni, 20, signed for the club in summer 2020 and almost opened the scoring against Tottenham in their recent history-making third round FA Cup clash.
He joined Rochdale's academy in 2016 before moving to Stalybridge Celtic in August 2018.
Manager Neil Young said: “Neil has done really well this season and has improved as the season as gone on.
"He still has a lot of development to do but he is very keen to improve and he has a very bright future if he keeps doing that."
Kengni added: “I’ve enjoyed my football with this amazing club."
"The players, staff and fans have supported me superbly and I can’t wait to carry on my fantastic journey with the club.”