Launcher Preferences
Tap the gear icon on the launcher home screen to open Settings.
Java / JRE Settings
CopperLauncher includes a built-in Java runtime downloader under Settings → Java Tweaks → Java Runtimes.
| Runtime | Status | Notes |
|---|---|---|
| Internal (Java 8) | Bundled — always available | Default for older Minecraft versions. Shown as 1.8.0_xxx |
| External 17 | Download in-app | Required for Minecraft 1.17–1.20 |
| External 21 | Download in-app | Required for Minecraft 1.21+ |
| External 25 | Download in-app | Latest — for future Minecraft versions |
To download a runtime, go to Settings → Java Tweaks → Java Runtimes, find the version you need, and tap DOWNLOAD. You can also tap ADD NEW to add a custom JRE, or DELETE RUNTIME to remove one.
CopperLauncher selects the correct Java version automatically based on the Minecraft version you launch. You only need to download an external runtime if your Minecraft version requires it.
| Setting | Description |
|---|---|
| Java Arguments | Custom JVM arguments — see Java Arguments guide |
| RAM Allocation | How much RAM to give Minecraft (default: auto) |
| Sandbox .jar execution | Controls the availability of the sandbox security manager when executing a .jar file |
Renderer Settings
The renderer is selected per-instance when creating a new instance. You can change it later in instance settings under Default controlmap.
| Renderer | Versions | Speed | Notes |
|---|---|---|---|
| Holy GL4ES | Up to 1.21.4 | Fast | Best compatibility for older versions |
| Zink (Vulkan) | All versions | Mid | Uses Vulkan via Zink translation layer |
| MobileGlues (OpenGL ES) | 1.17+ | Fast | Native OpenGL ES; great performance on modern devices |
| LTW (OpenGL ES 3) | 1.17+ | Fast | Lightweight OpenGL ES 3 renderer; good balance of compatibility and speed |
| Krypton Wrapper | Up to 1.21.8 | Fast | Wraps OpenGL calls for improved performance |
| Default | All versions | — | Uses the system default renderer |
If you are unsure which renderer to pick, try MobileGlues for Minecraft 1.17+ or Holy GL4ES for older versions.
Launcher Settings
| Setting | Description |
|---|---|
| Theme | Switch between Copper (default) and other themes |
| Language | Interface language (Crowdin community translations) |
| Show Log | Show the game log window during launch |
Experimental Settings
Experimental settings may cause instability. Use with caution.
| Setting | Description |
|---|---|
| Turbo Mode | Disables frame limiting for maximum performance |
| Force Vsync | Forces vertical sync |
| Use alternate surface | Alternative rendering surface (helps on some devices) |