Most restricted and unrestricted categories make use of glitches that were patched out (most notably, rope storage and i-frame on damage triggers). The most optimal patch currently (21th september 2024) is Ver 20240618xxxx.7fa8f8e6, which has Static Rope Storage, and added Jade Storage. You can find patchlists on the Tricks document

There's a few methods to downpatch the game:

Downpatching

For the steam version of the game, you can download old patches by using the Steam Console (or Depot Downloader in case the latter doesnt work), or by using the Steam Beta feature.

Steam Beta (speedrunner patch)

The lovely devs have made a steam beta branch we can downpatch to (and recently updated it to an optimal patch, thanks devs again). This branch updates us to the patch where Jade Storage was introduced. (18th June patch 7fa8f8e6)

To access this version, open the game properties in Steam

Enter the 'Betas' tab, and in Private Betas insert this code: speedrun20240618

Check code and opt in for the speedrunner branch

This will now enable the speedrunner branch as an option in Beta Participation. Choose the one you'd like to use

Using Steam Console (for other patches)

To access the Steam Console, you can open it by using this command in the browser, or on the Run Program (Win+R) feature in windows

steam://open/console

Inside the console, we'll be using the download_depot command to access previous versions of the game.

You can check the old versions in [this link], by going into the respective Depot for your OS (windows or mac), then into Manifests and checking the patch dates. We also have a list of patches where important tricks or glitches were removed inside the [Tricks Doc].

The command will be something like this (patch download commands might also be found in the tricks doc):

download_depot APP (1809540) DEPOT(Win/Mac) MANIFEST(patch)
Depot IDs: (1809541 for windows) (1809542 for mac)

For example:
download_depot 1809540 1809541 7607609690383614330

This should redownload the game files into a new folder located in "\Steam\steamapps\content\app_1809540\depot_(your OS referenced above)". When it finishes downloading and installing it will show in the console something like "Depot download complete: (game folder route here)"

After this, you can rename the folder (in case you want to download another patch later), then refer to the "Adding the game as Non-Steam Game" section.

Using Depot Downloader

Check this guide by BigNoNo (thanks)

After this, refer (again) to the "Adding the game as Non-Steam Game" section.

In case Steam Console stops working (again)

Adding the game as Non-Steam game

To make sure the previous options dont try to auto-update the game on opening, make sure you add (inside the downpatched game folder) a .txt file called "steam_appid.txt".

Inside that text file, just put the app number -> 1809540

This should allow the version to be opened without any issues. (You can maybe also make a copy of the speedrunner branch like this question mark)

After this you can add the game as a Non-Steam game inside the Steam Client for easier access to older versions.

Removing the version info on the top right

On some shipped versions, the debug version info on the top-right is still present, and this might not be wanted. You can remove this text by entering your game folder by editing config.json file inside the NineSols_Data/StreamingAssets/Config/ folders (with notepad or your text editor of choice), and emptying out the "Version" value (leave just a space), or changing it to something descriptive of the version.