This has been updated to properly download the bundle files that are needed.
Did a recent rust server update completely break your server this might help.

To get an older version of a Rust server go to Steamdb then click on patches.

From here find the version that you want on the list.


Now pick either Rust dedicated-win64 or Rust dedicated-linux64 for your use case then click the depot ID for the version you want.
On the same page, you will also need Rust dedicated-common. The Rust dedicated-common is required for both win64 and linux64.
This is because the Rust dedicated-common has the bundle files.


Write down the Depot ID, and Manifest ID for the operation system that you picked. Make sure you get the Correct Manifest ID.
Next, Write down the Depot ID and Manifest ID for the Rust dedicated-common.


This guide assumes you know how to use SteamCMD google is your friend.
Open up Steamcmd and put in these commands.

login anonymous
download_depot <appid> <depotid> [<target manifestid>]
(example) "download_depot 258550 258551 6716287437600842807"

There is no indication that the download has proceeded other than downloading depot (numberxxxxx...)
You will get a notification when it's finished. This process is slow.

Once downloaded you can now download the Rust dedicated-common.
download_depot <appid> <depotid> [<target manifestid>]

The package will download to a directory within Steamcmd. It will be listed in the console for the directory path.
Navigate to that directory and move it where you would like it. Example: where you might find it.
"C:\steamcmd\steamcmd\steamapps\content\app_258550\depot_258551"

Hope this helps.

Credit LizardMods, Timeconsumer, Raul