diff --git a/.scala-steward.conf b/.scala-steward.conf
index 4d97bf0..e546b9d 100644
--- a/.scala-steward.conf
+++ b/.scala-steward.conf
@@ -1,3 +1,3 @@
 updates.pin = [
-  { groupId = "org.scala-lang", artifactId = "scala3-library", version = "3.3." }
+  { groupId = "org.scala-lang", artifactId = "scala3-library", version = "3.9." }
 ]
diff --git a/build.sbt b/build.sbt
index ac191dd..279bf86 100644
--- a/build.sbt
+++ b/build.sbt
@@ -23,12 +23,12 @@ commonSmlBuildSettings
 ossPublishSettings
 
 organization := "com.softwaremill.chimp"
-scalaVersion := "3.3.8"
+scalaVersion := "3.9.0"
 Test / scalacOptions += "-Wconf:msg=unused value of type org.scalatest.Assertion:s"
 Test / scalacOptions += "-Wconf:msg=unused value of type org.scalatest.compatible.Assertion:s"
 Test / test / testOptions += Tests.Argument(TestFrameworks.ScalaTest, "-l", "Integration")
 Test / parallelExecution := false
-scalacOptions ++= Seq("-Wunused:all", "-Werror", "-Yfuture-lazy-vals", "-java-output-version", "11")
+scalacOptions ++= Seq("-Wunused:all", "-Werror", "-java-output-version", "17")
 
 val scalaTest = "org.scalatest" %% "scalatest" % scalaTestV % Test
 
diff --git a/client/src/main/scala/chimp/client/transport/ClientStdioTransport.scala b/client/src/main/scala/chimp/client/transport/ClientStdioTransport.scala
index db4f5f1..49dfa19 100644
--- a/client/src/main/scala/chimp/client/transport/ClientStdioTransport.scala
+++ b/client/src/main/scala/chimp/client/transport/ClientStdioTransport.scala
@@ -57,8 +57,8 @@ final class ClientStdioTransport(
   private val incomingHandler = AtomicReference[JSONRPCMessage => Identity[Unit]](_ => ())
   private val closed = AtomicBoolean(false)
 
-  private val readerThread = startDaemon("mcp-stdio-reader", readLoop _)
-  private val stderrThread = startDaemon("mcp-stdio-stderr", drainStderr _)
+  private val readerThread = startDaemon("mcp-stdio-reader", readLoop)
+  private val stderrThread = startDaemon("mcp-stdio-stderr", drainStderr)
 
   private def startDaemon(name: String, body: () => Unit): Thread =
     val thread = Thread(() => body())