Is a specific period of time stipulated for the obligation of shortening the prayer for a traveler, and what is this period if the traveler will reside for six months outside his homeland?

It is permissible for a traveler to shorten prayers (qasr) during a permissible journey if the distance reaches 83 kilometers or more, whether by land, sea, or air, unless he intends to reside for four days or more, or arrives at a place where he has a wife with whom he has consummated marriage. Shortening prayers is also permissible for someone who has stayed in a country for a need whose end is unknown, even if the time extends, unless he intends to reside for four days or more.