Hubbold, 27, has made 60 starts since joining the club in 2018.
Casson made the move to Borough Park in summer 2019, and has made 43 starts for the club.
Hubbold said: "I was over the moon to get the phone call from Danny (Grainger), just to know that he wanted me on his plans.
"Like most lads have said, it's a bonus to get it done early."
Grainger added: "Hubbold's his own biggest critic. I think a lot of him; he's creative, carries the ball well, passes it well, scores goals and he's a massive asset to the club and the team.
"Cass adapted to senior football really well in his first season. He quickly developed into one of the mainstays of the team and he's an unsung hero.
"His passing range, work rate and quality on the ball makes him a fantastic player, so hopefully he'll get back to those heights this season."