• Current Mixin Version: CleanMix 0.7.2 by CleanroomMC, a fork of SpongePowered/Fabric Mixin (0.8.7)

• Current MixinExtra Version: 0.5.5 by CleanroomMC

1. Add CleanroomMC's repository and depend on MixinBooter's maven entry:

repositories {
    maven {
        url ''
    }
}

dependencies {
    def mixin = 'zone.rong:mixinbooter:11.17'
    
    implementation (mixin) {
        transitive = false
    }
    annotationProcessor mixin

    // RetroFuturaGradle for refmap generation:
    modUtils.enableMixins(mixin)
    // modUtils.enableMixins(mixin, 'mod_id.mixins.refmap.json') << add refmap name as 2nd arg (optional)
}

2. Pick how to register your mixin configurations. MixinBooter supports lots of approaches:

(As of 11.0, early/late divide is no longer present, therefore IEarly/ILateMixinLoaders are deprecated)

• MixinConfigs manifest attribute: no loader class needed. Add a comma-separated list of your mixin configuration names to your jar's manifest. MixinBooter reads it straight from the jar's manifest and registers them.
• MixinConnector manifest attribute: register configs programmatically. Point it at a class implementing org.spongepowered.asm.mixin.connect.IMixinConnector, its connect() is called during boot, where you call Mixins.addConfiguration(...) yourself.

Both manifest attributes are set on your jar task:

jar {
    manifest {
        attributes(
                'MixinConfigs': 'mixins.mymod.json',
                'MixinConnector': 'com.example.mymod.MyMixinConnector'
        )
    }
}

public class MyMixinConnector implements IMixinConnector {
    
    @Override
    public void connect() {
        // Check if mod is loaded before registering?
        // Possible with zone.rong.mixinbooter.service.ModDiscoverer.isModPresent(String modId)
        Mixins.addConfiguration("mixins.mymod.json");
    }
    
}