In this post, I’ll walk through how I updated my Fabric mod project to target Minecraft 1.21.8 using the latest Fabric Loader, Yarn mappings, and Fabric API. This update also required upgrading Gradle, so I’ve included every step — including pitfalls I ran into and how I fixed them.

Step 1: Update gradle.properties

I updated my mod’s version configuration in gradle.properties. Here’s what changed:

Before:

minecraft_version=1.21.6
yarn_mappings=1.21.6+build.1
loader_version=0.16.14
loom_version=1.10-SNAPSHOT
fabric_version=0.128.0+1.21.6

After:

minecraft_version=1.21.8
yarn_mappings=1.21.8+build.1
loader_version=0.16.14
loom_version=1.11-SNAPSHOT
fabric_version=0.130.0+1.21.8

All versions were pulled from https://fabricmc.net/develop.

Step 2: Gradle Version Error

When I ran this to refresh dependencies:

./gradlew --refresh-dependencies

I got an error:

Plugin fabric-loom:1.11-SNAPSHOT requires at least Gradle 8.14, but this build uses 8.12.1.

Step 3: Manually Upgrade Gradle

Because the wrapper couldn’t upgrade itself (it failed during project configuration), I manually updated the Gradle wrapper version.

I edited this file:

gradle/wrapper/gradle-wrapper.properties

Changed this line:

- distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-bin.zip
+ distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip

Then I reran:

./gradlew --refresh-dependencies

And this time it succeeded.

Step 4: Unexpected Minecraft Version at Runtime

Even though gradle.properties now had minecraft_version=1.21.8, running the client still launched Minecraft 1.21.6!

That led to a mod resolution error:

Mod 'Fabric API' … requires Minecraft 1.21.8 … but 1.21.6 is loaded

I double-checked my build.gradle, and it was correctly referencing the property:

minecraft "com.mojang:minecraft:${project.minecraft_version}"

So I knew the config was fine — something else was stale.

Step 5: Regenerate IntelliJ Project Metadata

The fix was simple:

./gradlew genSources
./gradlew idea

These commands:

• Regenerated the mapped Minecraft sources
• Refreshed IntelliJ’s internal project and run configs

No IDE restart was required. Once these finished, launching the client correctly used:

Loading Minecraft 1.21.8 with Fabric Loader 0.16.14

Done!

At this point, my mod compiles, runs, and loads into Minecraft 1.21.8 with the latest Fabric API. The entire update took about 10 minutes once I figured out the Gradle version requirement and how to reset IntelliJ’s cached configs.

This post will serve as a reference for my future updates — and hopefully help others avoid the same pitfalls!