diff --git a/build.sbt b/build.sbt
index e31d5a2..332e23b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,7 +1,7 @@
 import Dependencies._
 import ReleaseTransformations._
 
-ThisBuild / scalaVersion := "2.12.20"
+ThisBuild / scalaVersion := "2.12.21"
 ThisBuild / versionScheme := Some("early-semver")
 
 addCommandAlias("ci", "; lint; test; scripted; publishLocal")
diff --git a/plugin/src/sbt-test/openapi-test/json-extra-scala/build.sbt b/plugin/src/sbt-test/openapi-test/json-extra-scala/build.sbt
index 428e736..ba7035d 100644
--- a/plugin/src/sbt-test/openapi-test/json-extra-scala/build.sbt
+++ b/plugin/src/sbt-test/openapi-test/json-extra-scala/build.sbt
@@ -2,7 +2,7 @@ import com.github.eikek.sbt.openapi._
 
 name := "sbt-openapi-simple-test"
 version := "0.0.1"
-scalaVersion := "2.12.20"
+scalaVersion := "2.12.21"
 
 libraryDependencies ++= Seq(
   "io.circe" %% "circe-generic-extras" % "0.11.1",
diff --git a/plugin/src/sbt-test/openapi-test/json-scala/build.sbt b/plugin/src/sbt-test/openapi-test/json-scala/build.sbt
index e0e55e5..c94bbb2 100644
--- a/plugin/src/sbt-test/openapi-test/json-scala/build.sbt
+++ b/plugin/src/sbt-test/openapi-test/json-scala/build.sbt
@@ -2,7 +2,7 @@ import com.github.eikek.sbt.openapi._
 
 name := "sbt-openapi-simple-test"
 version := "0.0.1"
-scalaVersion := "2.12.20"
+scalaVersion := "2.12.21"
 
 libraryDependencies ++= Seq(
   "io.circe" %% "circe-core" % "0.11.1",
diff --git a/plugin/src/sbt-test/openapi-test/simple-scala/build.sbt b/plugin/src/sbt-test/openapi-test/simple-scala/build.sbt
index b087b30..368a1ca 100644
--- a/plugin/src/sbt-test/openapi-test/simple-scala/build.sbt
+++ b/plugin/src/sbt-test/openapi-test/simple-scala/build.sbt
@@ -2,7 +2,7 @@ import com.github.eikek.sbt.openapi._
 
 name := "sbt-openapi-simple-scala-test"
 version := "0.0.1"
-scalaVersion := "2.12.20"
+scalaVersion := "2.12.21"
 
 enablePlugins(OpenApiSchema)
 openapiTargetLanguage := Language.Scala