diff --git a/build.sbt b/build.sbt
index b107b5aa..516913c2 100644
--- a/build.sbt
+++ b/build.sbt
@@ -34,7 +34,7 @@ ThisBuild / tlCiReleaseBranches := List("main", "feature/native-0.5")
 // use JDK 11
 ThisBuild / githubWorkflowJavaVersions := Seq(JavaSpec.temurin("11"))
 
-val scala212 = "2.12.20"
+val scala212 = "2.12.21"
 val scala213 = "2.13.18"
 ThisBuild / crossScalaVersions := Seq(scala212, scala213, "3.3.7")
 ThisBuild / scalaVersion       := scala213 // the default Scala