Are you talking about character growth/change or character "development" as in making your character three-dimensional and real?
Character growth/change is not mandatory. It depends on the story. Some character could even descend into madness or tragedy. But they can be exactly who they are from beginning to end, as long as that fits the story.
But character development (as in writing a well-developed character) is essential for good fiction, IMHO. Is it absolutely necessary? Not really, as evident in many stories with flat, cardboard characters, but personally I don't care for those stories that much. They may be thrill rides, but if I don't care about the characters, it's forgettable.
Example: Indiana Jones. He doesn't really change much from first movie to the last. He is who he is and he's a great character because the writers (and Harrison Ford) took care of developing his character and give him dimensions, including flaws. He's not this flat hero.
Yes. Very, very yes.
This is just a personal preference on my part, as a reader, but if there's little to no character development in any given story, I will see it as a waste of my time. I don't think it's necessary to spend several hundred pages on backstory or anything like that, but the characters have to be three-dimensional, unique, and at least a little relatable in order for me to care about them. If I don't care about them, I won't care what happens to them, and no amount of plot twists or clever word play will make that otherwise.
I don't mean that a character shouldn't be developed by the writer to have a personality; Shouldn't have depths and feelings and a history. That would be crazy.
I meant that so many of the books I read have the main character be developed and changed and affected by the story's events, so that by the end of it, his personality has changed from what it was in the beginning. And I don't have that, and haven't felt a need to say to myself: "Hmm, I feel Cody should become more focused and wise when this story is over, I'll have to dedicated a subplot to that."
But of course a central character should have A personality.