They will be coming

Archer: They told their homeworld how to find Earth.

T'Pol: Did you learn where the message was sent?

Archer: Somewhere deep in the Delta Quadrant.

T'Pol: Then I doubt there's any immediate danger. It would take at least 200 years for a subspace message to reach the Delta Quadrant, assuming it's received at all

Archer: Sounds to me like we've postponed the invasion until what, the 24th Century?