Upgrading DLC depots to 2021 versions (Steam downgrades DLC to 2017 version, replacing updated 2021 files)

It's been found that the 2021 update was meant to update the DLC packages too, but due to depot issues Steam overwrites the DLC with the older 2017 versions.

If you want to use the latest 2021 files, open your Steam library, right click NieR:Automata, open Properties, select the DLC tab, then uncheck all of the DLC listed there (besides the wallpaper set, if you have it).

Now select the "Local files" tab, and choose "Verify integrity of game files...", this'll take a little while, but once it's finished verifying Steam should start downloading the updated 2021 DLC files. 

Normally the game would disable the DLCs in-game if you had them disabled in Steam (even if you have the files available...), but as of LodMod v0.76.2 this has been fixed so the game just checks whether the files exist now.

(for reference, size of 2021 data100.cpk is 982,907,600 bytes)

Downgrading July 2021 update back to April 2017 build

Note: downgrading requires entering your Steam username/password into a third-party app!
The app is believed by many to be safe - users on PCGamingWiki & other sites have all mentioned using it, and I've been using it for years without issues, but I'm not responsible if anything happens with your account due to it!

As mentioned a few times on the LodMod page (and also in a small write-up here) it seems the old 2017 version of the game runs better than the new 2021 update, one cause for this could be due to compiler optimizations: seems 2021 had many optimizations disabled for some reason.

Fortunately downgrading to the 2017 build can be done pretty easily, with Kaldaien's FAR mod installed the 2017 version can run just as well as the 2021 build too (in fact even better than the 2021 build, since 2017 has far less stutter/latency issues!)

To start with you should have the latest NA version downloaded through Steam - this is used as a "base" for the downgrade to work on, since it includes all the DLC etc needed.

Now grab DepotDownloader from https://github.com/SteamRE/DepotDownloader/releases/latest, and extract the contents of that ZIP into the root of your NieRAutomata folder.

With that done, open a command-prompt inside your NieRAutomata folder (if you click the address bar and enter "cmd" and press enter, it should open a ready-to-use prompt for you)

Inside the prompt, enter the following command:

DepotDownloader.exe -app 524220 -depot 524221 -manifest 6804539827574949545 -validate -dir . -username [steam username] -password
(change [steam username] to your steam username)

Hit enter and you'll be prompted for your steam password, enter it in, if you have Steam Guard enabled you'll also need to check your email and enter the code into the command-prompt.

Now the 2017 build should start downloading & replacing your NA install, after it's finished you can close down the command-prompt.

With that done you've now downgraded your NieR install! To confirm it just check the size of NieRAutomata.exe, the 2017 version is 97,257,040 bytes.

Now you can download FAR to fix up the resolution/graphics issues (latest version for NA 2017 is https://github.com/Kaldaien/FAR/releases/download/far_070/FAR_0_7_0_23.7z, extract the DLL next to NieRAutomata.exe as dinput8.dll, first run of the game might exit out while it creates a config file, just launch the game again)

If FAR/SK asks whether you want to update make sure to select no & never ask again, since later SK versions sadly removed support for the 2017 build :(

The latest LodMod can also apply AO/LOD/shadow/culling improvements to the 2017 build fine too, just rename the LodMod DLL as xinput1_3.dll/dinput8.dll/dxgi.dll (or run it as a plugin through SK, as explained on main LodMod page)

Using updated 2021 data files with 2017 EXE

With LodMod v0.76 it's now possible to use the updated 2021 data files with the 2017 EXE, letting you make use of any updates/fixes that 2021 added to the data files (eg. some textures were changed & text strings were fixed, "Operator 210" -> "Operator 21O"...), with the better performance of the 2017 EXE.

All you need to do is copy the 2017 EXE into a 2021 install folder, and replace the 2021 data\movie\ & data\movie_logo\ folders with the 2017 versions, and as long as LodMod is installed correctly you should be able to launch this 2021-on-2017 install fine. (make sure the 2017 EXE is named NieRAutomata.exe - LodMod won't apply to any other filenames)

However, there's two parts 2021 updated which cause issues with 2017 though - the updated UI textures, and the shaders.

Fortunately those can be fixed pretty easily, either replace data000.cpk & data009.cpk with the 2017 versions, or extract the 2017 version of those CPK files using QuickBMS & cpk.bms, and then copy data000.cpk\shader.dat to the 2017 data\ folder, and the data009.cpk\ui\ folder to 2017's data\ui\ (folder will probably need to be created)

(note that other extraction tools might not completely extract the CPKs, at least some of the more common CPK tools recommended for NA seem to miss a bunch of the files in data009.cpk, but cpk.bms worked fine for me at least, and seems to fully extract them without issue)

With those in place the 2021-on-2017 game should hopefully run fine - UI should look normal and there shouldn't be any shader issues :) (https://i.imgur.com/T2weG23.jpeg is what happens when you don't replace shader.dat...)

I haven't tested this all that much yet though, possible that something was updated later in the game that causes issues, from what I've tried so far nothing strange has happened though (I'll update this post if I do find anything wrong with it)