Well, it seems the final "plan" released by the Spanish authorities with regard to the 700MHz clearance in 2019 onwards just refers to moving the existing DVB-T multiplexes down to below 700MHz.
Not much in the way of details. There may be a change to all MPEG4 or removing the SD simulcasts of the likes of La 1, La 2, Antena 3, Telecinco etc.