Because v1.9.1 is a legacy version (modern versions are 1.14+), the "proper" way to get this specific build is to use the official version-rollback feature provided by Paradox Interactive. Step 1: Purchase and Installation
Note: You can only play with others who are also specifically on v1.9.1. A Note on Third-Party Downloads Because v1
If you’ve played newer versions, go to Documents/Paradox Interactive/Hearts of Iron IV and delete the shadercache folder to prevent crashes. To play online with others on this specific
To play online with others on this specific version, everyone in the lobby must have the same "checksum" (the version code). Right-click in your Steam library. Select Properties > Betas . If you are looking for "free" download links
If you are looking for "free" download links or "cracked" online fixes, please be careful. Those files often contain malware or outdated "online-fix" DLLs that no longer work with Steam's current API. Using the official Steam rollback is the only way to ensure a stable, virus-free connection for multiplayer.
Steam will automatically download a small update to revert your game files to that 2020 version. Step 3: Enabling Online Play
This sounds like you are looking for a specific, older version of the (v1.9.1) to play online.