Hola Inma,
I can’t work out why whether the information is already known to the parties concerned, that the subjunctive is used [in the pretérito imperfecto].
Also why using the pretérito indefinido would indicate that the information is new information.
In other words what is the logic behind this when forming the subjunctive? I completely get the idea of a hypothetical idea requiring the subjunctive, but the aspect of whether the information is already familiar to the people concerned, is confusing me. Saludos. John