Theory's on traversable wormholes [ref 1], suggest that a readable wormhole can exist with negative energy detectable using the casimir effect in which an ordinary vacume produces negative energy.
Later theory's state that such a wormhole and there are many theorised that could naturally occur might be induced to traverse forwards in time by accelerating the other end close to the speed of light. Thus allowing forward movement to some future space and time. This would not violate causality unless you moved back the way and closed the door to the future or would it?
Is backward time travel negated somehow by this rule or as it would seem traversing a wormhole in either direction involves a passage through time fixed or otherwise.
It also raises the question of alignment. Can both ends be aligned after they've been moved in time. Would our spacetime's be in the same space.
Also if photons are moving through time always into the future relative to some fixed point then is it conceivable that the fixed point or observer could be slow down from this observation in his space and observe the future.