See I don't think it's as simple as that,
correctness shouldn't be about strict application of arbitrary rules; the purpose of grammar is to convey meaning, not to demand obedience. Sometimes I say "different from", and sometimes I say "different to", depending on the context; just as both "come from" and "come to", and both "go from" and "go to" can be correct, depending on what it is you are actually saying.

Always "differs from", though. I can't think of a single context in which "differs to" would make any sense.
( Moon Girl Technologies horrendous beanbag, Sat 10 Apr 2010, 15:11, Reply)