diff --git a/core/build.gradle.kts b/core/build.gradle.kts
index e5b8fa9ea..0ffde31f2 100644
--- a/core/build.gradle.kts
+++ b/core/build.gradle.kts
@@ -36,6 +36,7 @@ kotlin {
             target("watchosArm32")
             target("watchosArm64")
             target("watchosX86")
+            target("watchosX64")
             target("tvosArm64")
             target("tvosX64")
         }
@@ -152,7 +153,7 @@ kotlin {
         commonMain {
             dependencies {
                 api("org.jetbrains.kotlin:kotlin-stdlib-common")
-                compileOnly("org.jetbrains.kotlinx:kotlinx-serialization-core:$serializationVersion")
+                implementation("org.jetbrains.kotlinx:kotlinx-serialization-core:$serializationVersion")
             }
         }
 
@@ -192,7 +193,6 @@ kotlin {
         val jsMain by getting {
             dependencies {
                 api("org.jetbrains.kotlin:kotlin-stdlib-js")
-                api("org.jetbrains.kotlinx:kotlinx-serialization-core:$serializationVersion")
                 implementation(npm("@js-joda/core",  "3.2.0"))
             }
         }
@@ -206,9 +206,6 @@ kotlin {
 
         val nativeMain by getting {
             dependsOn(commonMain.get())
-            dependencies {
-                api("org.jetbrains.kotlinx:kotlinx-serialization-core:$serializationVersion")
-            }
         }
 
         val nativeTest by getting {
diff --git a/gradle.properties b/gradle.properties
index c8230af1d..8d179b829 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ group=org.jetbrains.kotlinx
 version=0.2.0
 versionSuffix=SNAPSHOT
 
-serializationVersion=1.1.0
+serializationVersion=1.2.1
 
 kotlin.mpp.enableGranularSourceSetsMetadata=true
 kotlin.mpp.enableCompatibilityMetadataVariant=true
diff --git a/serialization/build.gradle.kts b/serialization/build.gradle.kts
index 432f00a8a..b2949a42d 100644
--- a/serialization/build.gradle.kts
+++ b/serialization/build.gradle.kts
@@ -19,6 +19,7 @@ kotlin {
         target("watchosArm32")
         target("watchosArm64")
         target("watchosX86")
+        target("watchosX64")
         target("tvosArm64")
         target("tvosX64")
     }