Step 1: Create a Backup Before Changing Versions
Changing your Minecraft version — especially upgrading between major releases — permanently upgrades your world's chunk format. Chunks saved by a newer version cannot be safely read by an older server binary. Always take a snapshot backup before initiating a version change.
See How to Back Up and Restore Your Minecraft Server to create a locked snapshot in DustBowl Warden before proceeding.
Step 2: Changing the Version in DustBowl Warden
DustBowl Warden decouples container runtime configuration from disk storage, allowing clean version transitions:
- Log in to DustBowl Warden (
https://warden.dustbowl.games) and select your Minecraft server. - In the Console tab, type
stopto gracefully save world data and shut down the container. - Click the Startup tab in the top navigation bar.
- Locate the Minecraft Version variable.
- Enter or select your target version (for example,
1.21.4,1.20.4, or1.19.4). - Verify the Docker Image / Java Version setting against the runtime matrix:
| Minecraft Version Range | Required Java Runtime | Recommended Warden Container Image |
|---|---|---|
| 1.20.5 – 1.21.x+ | Java 21 | ghcr.io/pterodactyl/yolks:java_21 |
| 1.18 – 1.20.4 | Java 17 | ghcr.io/pterodactyl/yolks:java_17 |
| 1.17.x | Java 16 | ghcr.io/pterodactyl/yolks:java_16 |
| 1.12.2 – 1.16.5 | Java 8 / Java 11 | ghcr.io/pterodactyl/yolks:java_8 or java_11 |
- Navigate back to Console and click Start.
- Warden will pull the required server jar, apply the specified JVM flags, and launch the server. Confirm the startup line in the console:
[INFO] Starting minecraft server version 1.21.4
Upgrading to a Newer Version
Upgrading forwards (e.g., from 1.20.4 to 1.21.4) is supported by Minecraft's internal storage engine:
- Chunk Conversion: The server will convert chunks on demand as players load regions. For large worlds, consider running the
--forceUpgradestartup flag once or using the Chunky pre-generation plugin to convert chunks ahead of time. - Plugin and Mod Compatibility: Check Hangar, Modrinth, or SpigotMC for updated releases. Plugins compiled for older Bukkit versions may fail to enable.
- World Generation Features: New biomes and structures only generate in newly explored chunks.
Downgrading to an Older Version (Important Warning)
Caution
Never attempt to boot an existing world on an older Minecraft version (e.g., loading a 1.21 world with a 1.20 jar). Minecraft will encounter unmapped block IDs and unknown chunk metadata, causing chunks to reset or crash with ChunkFormatException.
If you need to downgrade:
- Revert the Minecraft Version and Java Version in Warden's Startup tab.
- Go to the Backups tab.
- Restore the snapshot backup created prior to your upgrade.
- Start the server.
Checking Your Current Version
To verify your active server build:
- In the Warden Console, enter:
version - In-game (as OP):
/version
This outputs the active Minecraft version, Paper/Purpur build hash, and whether updates are available.