Are both OK?
You are different from what I expected. and You are different than I expected.

Question

Are both OK?
You are different from what I expected.  and  You are different than I expected.

Answer

I don't have any English teachers told me " different than", but only taught me "different from".

Answer

Both are fine.

Answer

I usually say "Different from" but I know that some Americans say "different than". I think it was once considered incorrect but today it is accepted.