The term "outdated" is arguably harder to pinpoint than the term "old". A lot of films eventually become outdated, not because of anything the film does, but rather because of how the world has changed over time, and this is achieved through a number of different ways. However, I think it's wrong to say that "this film is outdated", because it's only usually a certain part of it, instead of the entire feature. Let's say that you have a 1990s comedy that makes a joke regarding disabled people. It's easy to argue that that is no longer an appropriate action to take these days, even if it's from 3 decades ago, because we've moved on and improved our understanding.
However, the problem with that view is that it implies that everyone has improved their understanding, and everyone labels the same things as appropriate and inappropriate. That doesn't really happen in the real world. Despite a lot of people now appreciating and supporting the black community in recent decades, some people still do not support them, and there will always be at least someone who doesn't, because it's a belief that they follow for their own reasons, and it's quite hard to explain why their belief is "wrong" or "inappropriate". Similarly, the same comedy with that disabled joke is entirely up for discussion as to whether it's appropriate or not, because everyone draws the line somewhere differently.
I think this links to the idea of whether or not a film's idea, joke, concept or what-have-you is something you believe personally or not. It is likely that you yourself will not make the same joke in real life, because you know the consequences of doing so, but creating that joke in a film causes a different effect, because it's for a particular reason. That doesn't mean the film's creators are like that in real life, they just wanted to make something that would make some people laugh. Not everyone, but some. All of this creates an entirely ambiguous definition of "outdated".