diff --git a/build.gradle.kts b/build.gradle.kts
index b487702..e65ccfe 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,10 +1,11 @@
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinMetadataTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
 
-val coroutinesVersion = "1.3.9"
-val atomicfuVersion = "0.14.4"
+val coroutinesVersion = "1.4.3"
+val atomicfuVersion = "0.15.0"
 
 plugins {
-    kotlin("multiplatform") version "1.4.21"
+    kotlin("multiplatform") version "1.4.32"
     id("org.jetbrains.dokka") version "0.10.0"
     id("maven-publish")
     id("signing")
@@ -36,19 +37,28 @@ kotlin {
             browser()
             nodejs()
         }
+    }
 
-        val nativeTargets = mutableListOf<KotlinNativeTarget>()
+    iosX64()
+    iosArm64()
+    iosArm32()
+    macosX64()
+    mingwX64()
+    linuxX64()
 
-        iosX64 { nativeTargets.add(this) }
-        iosArm64 { nativeTargets.add(this) }
-        iosArm32 { nativeTargets.add(this) }
-        macosX64 { nativeTargets.add(this) }
-        mingwX64 { nativeTargets.add(this) }
-        linuxX64 { nativeTargets.add(this) }
+    targets.withType<KotlinNativeTarget> {
+        val main by compilations.getting {
+            kotlinOptions.freeCompilerArgs = listOf("-Xopt-in=kotlin.RequiresOptIn")
+        }
+    }
 
-        nativeTargets.forEach {
-            val main by it.compilations.getting {
-                kotlinOptions.freeCompilerArgs = listOf("-Xuse-experimental=kotlin.Experimental")
+    // do this in afterEvaluate, when nativeMain compilation becomes available
+    afterEvaluate {
+        targets.withType<KotlinMetadataTarget> {
+            for (compilation in compilations) {
+                if (compilation.name == "nativeMain") {
+                    compilation.kotlinOptions.freeCompilerArgs = listOf("-Xopt-in=kotlin.RequiresOptIn")
+                }
             }
         }
     }
@@ -103,7 +113,7 @@ kotlin {
 val ktlintConfig by configurations.creating
 
 dependencies {
-    ktlintConfig("com.pinterest:ktlint:0.40.0")
+    ktlintConfig("com.pinterest:ktlint:0.41.0")
 }
 
 val ktlint by tasks.registering(JavaExec::class) {
diff --git a/gradle.properties b/gradle.properties
index 3784d67..de2e291 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1 +1,4 @@
-VERSION=0.6.3
+VERSION=0.6.4
+
+kotlin.mpp.enableGranularSourceSetsMetadata=true
+kotlin.mpp.enableCompatibilityMetadataVariant=true
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index da9702f..442d913 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/publish.gradle b/publish.gradle
index f8134e9..7cfc403 100644
--- a/publish.gradle
+++ b/publish.gradle
@@ -48,10 +48,6 @@ def getRepositoryPassword() {
     return System.getenv('SONATYPE_PASSWORD') ?: ''
 }
 
-task emptySourcesJar(type: Jar) {
-    classifier = 'sources'
-}
-
 task javadocsJar(type: Jar, dependsOn: dokka) {
     classifier = 'javadoc'
     from dokka.outputDirectory
@@ -94,13 +90,6 @@ publishing {
         }
     }
 
-    afterEvaluate {
-        publications.getByName('kotlinMultiplatform') {
-            // Source jars are only created for platforms, not the common artifact.
-            artifact emptySourcesJar
-        }
-    }
-
     repositories {
         maven {
             url isReleaseBuild() ? getReleaseRepositoryUrl() : getSnapshotRepositoryUrl()
@@ -127,7 +116,6 @@ tasks.register('publishMac') {
     dependsOn 'publishIosX64PublicationToMavenRepository'
     dependsOn 'publishMacosX64PublicationToMavenRepository'
     dependsOn 'publishJvmPublicationToMavenRepository'
-    dependsOn 'publishMetadataPublicationToMavenRepository'
     dependsOn 'publishKotlinMultiplatformPublicationToMavenRepository'
     dependsOn 'publishJsPublicationToMavenRepository'
 }