diff --git a/src/Pure/Admin/build_scala.scala b/src/Pure/Admin/build_scala.scala
--- a/src/Pure/Admin/build_scala.scala
+++ b/src/Pure/Admin/build_scala.scala
@@ -1,163 +1,163 @@
 /*  Title:      Pure/Admin/build_scala.scala
     Author:     Makarius
 
 Build Isabelle Scala component from official downloads.
 */
 
 package isabelle
 
 
 object Build_Scala {
   /* downloads */
 
   sealed case class Download(
     name: String,
     version: String,
     url: String,
     physical_url: String = "",
     base_version: String = "3"
   ) {
     def make_url(template: String): String =
       template.replace("{V}", version).replace("{B}", base_version)
 
     def proper_url: String = make_url(proper_string(physical_url).getOrElse(url))
 
     def artifact: String =
       Library.take_suffix[Char](_ != '/', proper_url.toList)._2.mkString
 
     def get(path: Path, progress: Progress = new Progress): Unit =
       Isabelle_System.download_file(proper_url, path, progress = progress)
 
     def get_unpacked(dir: Path, strip: Int = 0, progress: Progress = new Progress): Unit =
       Isabelle_System.with_tmp_file("archive"){ archive_path =>
         get(archive_path, progress = progress)
         progress.echo("Unpacking " + artifact)
         Isabelle_System.gnutar(
           "-xzf " + File.bash_path(archive_path), dir = dir, strip = strip).check
       }
 
     def print: String =
       "  * " + name + " " + version +
         (if (base_version.nonEmpty) " for Scala " + base_version else "") +
         ":\n    " + make_url(url)
   }
 
   val main_download: Download =
-    Download("scala", "3.1.1", base_version = "",
+    Download("scala", "3.1.3", base_version = "",
       url = "https://github.com/lampepfl/dotty/releases/download/{V}/scala3-{V}.tar.gz")
 
   val lib_downloads: List[Download] = List(
     Download("scala-parallel-collections", "1.0.4",
       "https://mvnrepository.com/artifact/org.scala-lang.modules/scala-parallel-collections_{B}/{V}",
       physical_url = "https://repo1.maven.org/maven2/org/scala-lang/modules/scala-parallel-collections_{B}/{V}/scala-parallel-collections_{B}-{V}.jar"),
     Download("scala-parser-combinators", "2.1.1",
       "https://mvnrepository.com/artifact/org.scala-lang.modules/scala-parser-combinators_{B}/{V}",
       physical_url = "https://repo1.maven.org/maven2/org/scala-lang/modules/scala-parser-combinators_{B}/{V}/scala-parser-combinators_{B}-{V}.jar"),
     Download("scala-swing", "3.0.0",
       "https://mvnrepository.com/artifact/org.scala-lang.modules/scala-swing_{B}/{V}",
       physical_url = "https://repo1.maven.org/maven2/org/scala-lang/modules/scala-swing_{B}/{V}/scala-swing_{B}-{V}.jar"),
     Download("scala-xml", "2.1.0",
       "https://mvnrepository.com/artifact/org.scala-lang.modules/scala-xml_{B}/{V}",
       physical_url = "https://repo1.maven.org/maven2/org/scala-lang/modules/scala-xml_{B}/{V}/scala-xml_{B}-{V}.jar")
   )
 
 
   /* build Scala component */
 
   def build_scala(
     target_dir: Path = Path.current,
     progress: Progress = new Progress
   ): Unit = {
     /* component */
 
     val component_name = main_download.name + "-" + main_download.version
     val component_dir = Isabelle_System.new_directory(target_dir + Path.basic(component_name))
     progress.echo("Component " + component_dir)
 
 
     /* download */
 
     main_download.get_unpacked(component_dir, strip = 1, progress = progress)
 
     val lib_dir = component_dir + Path.explode("lib")
     lib_downloads.foreach(download =>
       download.get(lib_dir + Path.basic(download.artifact), progress = progress))
 
     File.write(component_dir + Path.basic("LICENSE"),
       Url.read(Url("https://www.apache.org/licenses/LICENSE-2.0.txt")))
 
 
     /* classpath */
 
     val classpath: List[String] = {
       def no_function(name: String): String = "function " + name + "() {\n:\n}"
       val script =
         cat_lines(List(
           no_function("stty"),
           no_function("tput"),
           "PROG_HOME=" + File.bash_path(component_dir),
           File.read(component_dir + Path.explode("bin/common"))
             .replace("scala_exit_status=127", "scala_exit_status=0"),
           "compilerJavaClasspathArgs",
           "echo \"$jvm_cp_args\""))
 
       val main_classpath = Path.split(Isabelle_System.bash(script).check.out).map(_.file_name)
       val lib_classpath = lib_downloads.map(_.artifact)
 
       main_classpath ::: lib_classpath
     }
 
     val interfaces =
       classpath.find(_.startsWith("scala3-interfaces"))
         .getOrElse(error("Missing jar for scala3-interfaces"))
 
 
     /* settings */
 
     val etc_dir = Isabelle_System.make_directory(component_dir + Path.basic("etc"))
     File.write(etc_dir + Path.basic("settings"),
       """# -*- shell-script -*- :mode=shellscript:
 
 SCALA_HOME="$COMPONENT"
 SCALA_INTERFACES="$SCALA_HOME/lib/""" + interfaces + """"
 """ + terminate_lines(classpath.map(jar => "classpath \"$SCALA_HOME/lib/" + jar + "\"")))
 
 
     /* README */
 
     File.write(component_dir + Path.basic("README"),
       "This distribution of Scala integrates the following parts:\n\n" +
       (main_download :: lib_downloads).map(_.print).mkString("\n\n") + """
 
 
         Makarius
         """ + Date.Format.date(Date.now()) + "\n")
   }
 
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool =
     Isabelle_Tool("build_scala", "build Isabelle Scala component from official downloads",
       Scala_Project.here,
       { args =>
         var target_dir = Path.current
 
         val getopts = Getopts("""
 Usage: isabelle build_scala [OPTIONS]
 
   Options are:
     -D DIR       target directory (default ".")
 
   Build Isabelle Scala component from official downloads.
 """,
           "D:" -> (arg => target_dir = Path.explode(arg)))
 
         val more_args = getopts(args)
         if (more_args.nonEmpty) getopts.usage()
 
         val progress = new Console_Progress()
 
         build_scala(target_dir = target_dir, progress = progress)
       })
 }