diff --git a/modules/core/src/test/scala/jsonrpclib/RawMessageSpec.scala b/modules/core/src/test/scala/jsonrpclib/RawMessageSpec.scala
index c669629..c8f8ada 100644
--- a/modules/core/src/test/scala/jsonrpclib/RawMessageSpec.scala
+++ b/modules/core/src/test/scala/jsonrpclib/RawMessageSpec.scala
@@ -116,17 +116,17 @@ object RawMessageSpec extends FunSuite {
 
     expect.same(
       decodeInput("""{"jsonrpc":"2.0","method":"greet","id":1}"""),
-      Right(InputMessage.RequestMessage("greet", CallId.NumberId(1), None))
+      Right(InputMessage.RequestMessage("greet", CallId.NumberId(1), Payload.Empty))
     ) &&
     expect.same(
       decodeInput("""{"jsonrpc":"2.0","method":"ping"}"""),
-      Right(InputMessage.NotificationMessage("ping", None))
+      Right(InputMessage.NotificationMessage("ping", Payload.Empty))
     ) &&
     expect(decodeInput("""{"jsonrpc":"2.0","id":1,"result":null}""").isLeft)
   }
 
   test("input message codec serializes via Message encoder") {
-    val input: InputMessage = InputMessage.RequestMessage("greet", CallId.NumberId(0), None)
+    val input: InputMessage = InputMessage.RequestMessage("greet", CallId.NumberId(0), Payload.Empty)
     val expected = """{"jsonrpc":"2.0","method":"greet","id":0}"""
 
     expect(writeToString(input.asJson) == expected)
diff --git a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonNotificationOutputValidatorSpec.scala b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonNotificationOutputValidatorSpec.scala
index 0fe058c..de2b4d7 100644
--- a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonNotificationOutputValidatorSpec.scala
+++ b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonNotificationOutputValidatorSpec.scala
@@ -19,7 +19,7 @@ object JsonNotificationOutputValidatorSpec extends FunSuite {
         |operation NotifySomething {
         |}
         |""".stripMargin
-    )
+    ): Unit
     success
   }
   test("return an error when a @jsonNotification operation does not have unit output") {
diff --git a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonRpcOperationValidatorSpec.scala b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonRpcOperationValidatorSpec.scala
index 6c4815a..e06250c 100644
--- a/modules/smithy-tests/src/test/scala/jsonrpclib/JsonRpcOperationValidatorSpec.scala
+++ b/modules/smithy-tests/src/test/scala/jsonrpclib/JsonRpcOperationValidatorSpec.scala
@@ -30,7 +30,7 @@ object JsonRpcOperationValidatorSpec extends FunSuite {
         |  output: unit
         |}
         |""".stripMargin
-    )
+    ): Unit
     success
   }
 
diff --git a/project/build.properties b/project/build.properties
index df061f4..dabdb15 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.12.9
+sbt.version=1.12.11
diff --git a/project/plugins.sbt b/project/plugins.sbt
index e8b2c88..1b84e5b 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,8 +1,8 @@
-addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.11.1")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.11.2")
 
-addSbtPlugin("org.typelevel" % "sbt-tpolecat" % "0.5.2")
+addSbtPlugin("org.typelevel" % "sbt-tpolecat" % "0.5.3")
 
-addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.1")
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.5")
 
 addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.10.0")
 
@@ -12,10 +12,10 @@ addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.5.11")
 
 addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.3.1")
 
-addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.4")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.6.0")
 
-addSbtPlugin("com.disneystreaming.smithy4s" % "smithy4s-sbt-codegen" % "0.18.51")
+addSbtPlugin("com.disneystreaming.smithy4s" % "smithy4s-sbt-codegen" % "0.19.7")
 
-addSbtPlugin("org.polyvariant" % "smithy-trait-codegen-sbt" % "0.2.2")
+addSbtPlugin("org.polyvariant" % "smithy-scala-tools-sbt" % "0.3.1")
 
 addDependencyTreePlugin