If you are planning to import an old save to finish the game in its new shiny coat:
The Remaster is a from the original game, meaning you must download the entire client (approx. 90-100GB) rather than a small patch. Horizon Zero Dawn™ Remastered - Steam Community
If you are planning to import an old save to finish the game in its new shiny coat:
The Remaster is a from the original game, meaning you must download the entire client (approx. 90-100GB) rather than a small patch. Horizon Zero Dawn™ Remastered - Steam Community horizon zero dawn remastered update v1589 install