diff --git a/build.sbt b/build.sbt
index fe827ff..c8f449e 100644
--- a/build.sbt
+++ b/build.sbt
@@ -15,7 +15,7 @@ ThisBuild / developers := List(
 ThisBuild / tlSitePublishBranch := Some("main")
 
 val Scala213 = "2.13.18"
-ThisBuild / crossScalaVersions := Seq(Scala213, "3.3.8")
+ThisBuild / crossScalaVersions := Seq(Scala213, "3.3.9")
 ThisBuild / scalaVersion := Scala213 // the default Scala
 
 lazy val root = tlCrossRootProject.aggregate(core, mtl, testkit, circe)