The club’s manager will remain until 2021, they announced on Tuesday night.
Strevens enjoyed a great first season in the dug-out as the Spitfires defied the odds to complete for promotion.
They almost pulled it off but lost out in heartbreaking fashion to Salford City on penalties in the play-off semi-final.
“I’m delighted to get it all signed and all done, I think it was important for me and the management team after last season the club has shown a lot of faith in us,” he told the club’s website.
“After last season it was a case of putting our own personal situations to one side to sort out the squad.
“We really have to build on what we did last year, keep working hard and now it’s a long-term project and hopefully a successful one.”