In the Windows Phone GDR3 feature list, support for an additional row column will be included the start screen. This resulted in a position to fit three medium-sized square tiles in one row as opposed to the limit of two today. That which was unclear until now was if this additional column is going to be for 1080p devices only or 720p or WVGA devices as well.
The news was confirmed by Joe Belfiore, VP of the Windows Phone program at Microsoft so it's as official as it gets. His tweet also mentions other UI changes the GDR3 update brings specially for 1080p smartphones. The first of them is anticipated to be the Nokia Lumia 1520, which is most likely todebut at the Nokia event in Abu Dabu on October 22.
The Windows Phone 8 GDR3 update rollout will commence in the coming weeks and will continue over several months. Microsoft can't give specific timing as it depends on the user's carrier and make contact with model.