diff --git a/build.sbt b/build.sbt
index 9b0abc86f..71b14cfc3 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,9 +1,8 @@
 import java.io.File
 import java.nio.charset.Charset
-import java.nio.file.Files
-
+import java.nio.file.{Files, StandardCopyOption}
 import com.typesafe.sbt.packager.linux.{LinuxPackageMapping, LinuxSymlink}
-import sbt.Keys._
+import sbt.Keys.*
 
 resolvers ++= Resolver.sonatypeOssRepos("public")
 
@@ -217,7 +216,7 @@ lazy val generateVersionTask = Def.task {
   */
 lazy val buildNpmJsFile = taskKey[Seq[File]]("buildNpmJsFile")
 lazy val buildNpmJsFileTask = Def.task {
-  val compiledFile = target.value / "scala-2.12" / s"${name.value}-fastopt.js"
+  val compiledFile = target.value / "scala-2.13" / s"${name.value}-fastopt.js"
   println(s"buildNpmJsFile: reading $compiledFile")
   val compiledFileContents = IO.read(compiledFile, UTF8)
 
@@ -249,8 +248,8 @@ lazy val buildNpmPackageTask = Def.task {
   val readMeFile = new File("js/npm/README.md")
   val packageJsonFile = new File("js/npm/package.json")
 
-  Files.copy(new File("LICENSE").toPath, licenseFile.toPath)
-  Files.copy(new File("js/README.md").toPath, readMeFile.toPath)
+  Files.copy(new File("LICENSE").toPath, licenseFile.toPath, StandardCopyOption.REPLACE_EXISTING)
+  Files.copy(new File("js/README.md").toPath, readMeFile.toPath, StandardCopyOption.REPLACE_EXISTING)
 
   val packageJsonTmpl = IO.read(new File("js/package.json"), UTF8)
   val packageJsonContents = packageJsonTmpl.replaceFirst(
diff --git a/jvm/src/main/scala/io/kaitai/struct/JavaMain.scala b/jvm/src/main/scala/io/kaitai/struct/JavaMain.scala
index eb8c3b91d..efd3b3bdb 100644
--- a/jvm/src/main/scala/io/kaitai/struct/JavaMain.scala
+++ b/jvm/src/main/scala/io/kaitai/struct/JavaMain.scala
@@ -190,13 +190,13 @@ object JavaMain {
     // we need to decode it as well.
     //
     // Linux, from IDE:
-    // $HOME/git/kaitai_struct/compiler/jvm/target/scala-2.12/classes/
+    // $HOME/git/kaitai_struct/compiler/jvm/target/scala-2.13/classes/
     //
     // Linux, from stage:
     // $HOME/git/kaitai_struct/compiler/jvm/target/universal/stage/lib/io.kaitai.kaitai-struct-compiler-0.10-SNAPSHOT.jar
     //
     // Linux, from "sbt compilerJVM/run"
-    // $HOME/git/kaitai_struct/compiler/jvm/target/scala-2.12/classes/
+    // $HOME/git/kaitai_struct/compiler/jvm/target/scala-2.13/classes/
     //
     // Linux, from universal, custom install path:
     // /tmp/a%20b/kaitai-struct-compiler-0.10-SNAPSHOT/lib/io.kaitai.kaitai-struct-compiler-0.10-SNAPSHOT.jar