Let me answer some questions that came up here.
This works with all versions of the game, physical and digital, standard and complete edition (aka. Game of the Year). You will receive the upgrade for the version of the game you own. If you only own the base game, without the expansions, you will receive the base game, not the complete edition. If you own the game on the physical disc, you will have to insert it to the console to play it.
This update is not dedicated to fixing existing bugs or adding new content, but to upgrading the current-gen version of the game when it is being played on the Xbox Series X and PlayStation 5 hardware. That means, among others, 4K, ray-tracing and faster lading times on next-gen consoles as well as ray-tracing and HDR for PC.
The update won’t change the game’s minimum requirements for PC, but in order to fully take advantage of it you, of course, need to have the appropriate hardware.