Performance VPS
Foundational VPS
VDS
Specialty Servers
Domain Names
Colocation
Startup Variables and Docker Images
Change your game version, server jar, or runtime from the panel Startup tab, learn which variables you can edit, and recover when a change breaks startup.
The Startup tab is where a game server's launch is configured: which version or jar it runs, how much memory it gets, the map or game mode it boots into, and which runtime image (for example, which Java version) wraps it. Most "how do I change the version" and "how do I switch to Paper or Forge" questions end here. Reach the panel as described in Access Your Game Server Panel.
What is on the tab#
- Startup Command
- The command the panel runs to launch your server, shown for reference. Placeholders such as
{{SERVER_MEMORY}}and{{SERVER_PORT}}are filled in from your plan and your primary allocation when the server starts. You do not edit this line directly; you change the variables that feed it. - Docker Image
- The runtime the server runs inside. For Java games this is effectively the Java version (Java 8, 11, 17, or 21). Only the images approved for your server type are offered; if the one you need is missing, open a ticket.
- Variables
- One card per setting the server type exposes: version, build, jar file, world name, max players, game mode, Steam App ID, and so on. Each shows a description and the current value; some are read-only because they are managed for you.
Change a variable#
- Stop the server (or at least save the world) if the change affects files on disk, such as switching server jar or version.
- Edit the value in the variable's field. Values are validated as you save: a version field only accepts a real version string, a numeric field only numbers. A red message means the value was rejected and nothing changed.
- Restart the server. Startup variables are read only at launch, so nothing changes until the next start.
- Watch the console. The Console shows the new version downloading or the new jar loading, and any errors if it does not.
Common recipes#
Update Minecraft to a newer version#
Set the version variable (for example 1.21.4, or latest where supported), and the build variable to latest for Paper or Purpur. Take a backup first: worlds upgrade forward, never back. If the new version needs a newer Java, switch the Docker Image to match (Minecraft 1.17 and newer need Java 17 or later; 1.20.5 and newer need Java 21).
Switch to Paper, Fabric, or Forge#
Where your server type exposes a jar or loader variable, changing it swaps the software; a Forge or Fabric loader will then need mods uploaded through the file manager or SFTP. If the option is not present, the switch requires a different server type on our side; ask in a ticket and we will move you at no charge.
Change memory or the port#
Memory is set by your plan and the port by your primary allocation; both are injected automatically. To change them, upgrade the plan or make a different allocation primary.
Note what you changed and when in the schedule or a text file in the server root. When something breaks after "an update", the Startup tab and the Activity log together tell you exactly which change to roll back.
Something will not start after a change#
- Read the last 50 lines of the console; the game usually names the file or setting it dislikes.
- Set the variable back to its previous value and restart. If it starts, the new value was the problem.
- Java version mismatch ("class file version" errors) means the Docker Image and the game version disagree.
- Still stuck? A reinstall re-downloads clean server files while keeping your backups, and a ticket with the console output gets an engineer's eyes on it.
