diff --git a/build.sbt b/build.sbt
index d4355b6..d2e746f 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,6 +1,6 @@
 name := "codacy-api-scala"
 
-scalaVersion := "2.12.20"
+scalaVersion := "2.13.17"
 scalacOptions := Seq("-deprecation", "-feature", "-unchecked", "-Ywarn-adapted-args", "-Xlint", "-Xfatal-warnings")
 
 // Runtime dependencies
diff --git a/src/main/scala/com/codacy/api/CoverageReport.scala b/src/main/scala/com/codacy/api/CoverageReport.scala
index f4e6641..805c13b 100644
--- a/src/main/scala/com/codacy/api/CoverageReport.scala
+++ b/src/main/scala/com/codacy/api/CoverageReport.scala
@@ -8,7 +8,7 @@ case class CoverageReport(fileReports: Seq[CoverageFileReport])
 
 object CoverageReport {
   implicit val mapWrites: Writes[Map[Int, Int]] = Writes[Map[Int, Int]] { map: Map[Int, Int] =>
-    JsObject(map.map {
+    JsObject(map.iterator.map {
       case (key, value) => (key.toString, JsNumber(value))
     }(collection.breakOut))
   }