Which version should I launch?
Use Minecraft Java Edition 26.2 for the current Unstable SMP joining instructions. Save a named installation for that version instead of relying on “Latest Release,” which can change when Minecraft updates.
A launcher update and a game-version update are different things. You can keep the official launcher updated while selecting a particular Java release for a server. If the server later announces a new required version, update your saved installation to match.
Create a named installation
- Open the official Minecraft Launcher and choose Minecraft: Java Edition.
- Open Installations and choose New installation. Give it a recognizable name, such as Unstable SMP — Java 26.2.
- In the version selector, choose the release for 26.2. Avoid a snapshot or pre-release with a similar name.
- Save the installation. Return to Play, select that named installation, and launch it. Allow the launcher to download the required files.
- Check the version shown in the game before opening Multiplayer. Save play.unstablesmp.gg as the server address, without a web prefix or appended port.
Menu labels may differ with launcher language. The joining walkthrough covers the Multiplayer and Add Server screens after the correct game version is running.
If the version is missing from the list
Confirm that you selected Java Edition and that release installations are visible. Restart the official launcher after any pending launcher update, then look again. Read the entire version label: a snapshot, pre-release, or release candidate is not interchangeable with the named release.
If the required release still is not available, check the current server announcement before downloading anything else. Do not install a game file sent through a direct message to “unlock” a version. Get the launcher from Minecraft's official download page.
Make a clean comparison if you use mods
When a modified client fails, a second installation of the same unmodified release helps separate a local client problem from a server problem. Create a separate game directory for the test in the installation settings so it does not reuse your usual mods, settings, resource packs, or saves. Keep the original directory intact.
A new installation name alone does not isolate those files if it uses the same directory. Avoid deleting your normal Minecraft folder. You do not need to move or open your single-player worlds to test a multiplayer connection.
Protect worlds when changing versions
Opening a single-player world in a different game version can change its saved data. Back up worlds before upgrading them, and do not use a valuable world to experiment with an older release. Selecting another client version for multiplayer does not require converting your local worlds.
If the version matches but the connection still fails
Keep the exact error. “Unknown Host” points toward address resolution; a timeout concerns reaching a response; a sign-in error needs account-session checks. Reinstalling the game repeatedly does not distinguish these causes. Use the error-by-error fixes and include whether a clean client made any difference when asking for help.