diff --git a/build.sbt b/build.sbt
index 0d3f198ac1..5a5087d435 100644
--- a/build.sbt
+++ b/build.sbt
@@ -78,8 +78,8 @@ def jdk11GcJavaOptions: Seq[String] = {
 }
 
 val defaultProjectSettings = Seq(
-  scalaVersion := "2.12.12",
-  crossScalaVersions := Seq("2.12.12", "2.13.1")
+  scalaVersion := "2.13.6",
+  crossScalaVersions := Seq("2.12.12", "2.13.6")
 )
 
 val baseSettings = Seq(
diff --git a/util-validator/src/main/scala/com/twitter/util/validation/ScalaValidator.scala b/util-validator/src/main/scala/com/twitter/util/validation/ScalaValidator.scala
index bca0626154..f748aec4f6 100644
--- a/util-validator/src/main/scala/com/twitter/util/validation/ScalaValidator.scala
+++ b/util-validator/src/main/scala/com/twitter/util/validation/ScalaValidator.scala
@@ -860,12 +860,12 @@ class ScalaValidator private[validation] (
     val results = new mutable.ListBuffer[ConstraintViolation[T]]()
     val parameters: Array[Parameter] = executableDescriptor.executable.getParameters
     val parameterNamesList: Array[String] =
-      parameterNames match {
+      (parameterNames match {
         case Some(names) =>
           names
         case _ =>
           getExecutableParameterNames(executableDescriptor.executable)
-      }
+      }).map(DescriptorFactory.unmangleName) // parameter names are encoded since Scala 2.13.5
 
     // executable parameter constraints
     var index = 0