Cyberpunk 2077 OPEN//77: install the mod and join a server

OPEN//77 is an independent multiplayer mod. Its public Alpha lets you join community servers without an invitation or application. The servers run their own game modes; this is separate from the base game’s single-player campaign.

Check three versions before installing

What you’re checking	What to look for
Cyberpunk 2077 and Phantom Liberty	A legitimately owned PC copy, exactly 2.5, with Phantom Liberty installed. The project checks the executable; a later game patch is not automatically compatible.
Windows launcher	Use the project’s download page. On November 13 it listed Windows launcher 2.50.0+op77.210. The older .149 in the launcher guide describes recovery from a previous update.
Multiplayer client and server	Let the launcher install or update the client. The same download page listed the dedicated server at 2.50.0+op77.223 on November 13 and says the client is versioned with the server build it uses. The server package is for the host.

These steps cover the documented Windows player setup. The download page also lists a Linux launcher preview and a separate Linux hosting package. The preview listing does not change the documented Windows player requirements for this walkthrough.

Install the client and enter a world

1. Open the project’s download page and choose the Windows launcher. The project says the executable is unsigned and publishes a SHA-256 checksum beside the file. Follow your device’s security policy if it is blocked.
2. Open the launcher and sign in through your browser with your free OPEN//77 account. Let the launcher find and verify the game. If it asks for a location, point it to the folder containing the game. The guide says Epic installs need manual selection.
3. Close Cyberpunk 2077 before applying the multiplayer update. If the launcher offers an update for itself, finish that and reopen it; the client update is separate.
4. Pick a world in the launcher or compare it with the live server directory. To join a friend’s unlisted server, ask for the reachable address and port, then enter hostname:port in Direct Connect. Private addresses may be absent from the directory, and an Unknown status does not tell you whether a host is online.

Direct Connect still uses your OPEN//77 sign-in and the server’s access rules. If the host has a password or whitelist, ask them how to get access.

Find what failed before changing your install

Symptom	Try next	What it tells you
Game not found or build warning	Check the folder, executable, installed expansion and exact supported build. The launcher docs describe the read-only –detect-only check.	The launcher can warn before the join service rejects the build. If the game has moved past the supported build, check the project’s updates before changing game files.
The public list is empty	Clear filters and refresh. Check that the launcher uses Open//77 Alpha with Stable updates. Local development looks at a separate directory. Compare the web directory and service status.	If the web directory shows worlds but your launcher does not, record the launcher’s directory and update settings before reinstalling.
Only one server refuses the join	Confirm the address, port and admission rules with the host. Compare with a public world that allows new players.	If another world works, ask the first operator about its server build and resources. The launcher guide says a server still on 2.31 cannot accept a 2.5 client.
Every server fails or Alpha approval reappears	Check the current launcher download, update the client on Stable, sign in again and record the exact error.	Open Alpha does not require approval. A stale launcher, expired session or failed update is more useful to investigate than applying again.

For project support, gather the game build, launcher and client versions, target server, error text and approximate time. The launcher writes a log under %LOCALAPPDATA%/Open77/launcher.log. Review it for private information before sharing. Keep a separate backup of important single-player saves before changing any mod setup.