diff --git a/build.sc b/build.sc
index a966199ac82..3a2445b00f5 100644
--- a/build.sc
+++ b/build.sc
@@ -521,14 +521,14 @@ object main extends MillStableScalaModule with BuildInfo {
       trait CaseModule extends ScalaModule with Cross.Module[String] {
         def caseName = crossValue
         object external extends ScalaModule {
-          def scalaVersion = "2.13.10"
+          def scalaVersion = Deps.scalaVersion
         }
 
         def moduleDeps = Seq(external)
 
         val Array(prefix, suffix, rest) = caseName.split("-", 3)
         def millSourcePath = super.millSourcePath / prefix / suffix / rest
-        def scalaVersion = "2.13.10"
+        def scalaVersion = Deps.scalaVersion
         def ivyDeps = T {
           if (!caseName.contains("realistic") && !caseName.contains("sourcecode")) super.ivyDeps()
           else Agg(
diff --git a/integration/feature/watch-source-input/test/src/WatchSourceInputTests.scala b/integration/feature/watch-source-input/test/src/WatchSourceInputTests.scala
index febd6b21690..0668d792ed1 100644
--- a/integration/feature/watch-source-input/test/src/WatchSourceInputTests.scala
+++ b/integration/feature/watch-source-input/test/src/WatchSourceInputTests.scala
@@ -47,6 +47,7 @@ object WatchSourceInputTests extends IntegrationTestSuite {
       val res = f(expectedOut, expectedErr, expectedShows)
       val (shows, out) = res.out.linesIterator.toVector.partition(_.startsWith("\""))
       val err = res.err.linesIterator.toVector
+        .filter(!_.contains("Compiling compiler interface..."))
         .filter(!_.contains("Watching for changes"))
         .filter(!_.contains("[info] compiling"))
         .filter(!_.contains("[info] done compiling"))
diff --git a/runner/src/mill/runner/MillBuildRootModule.scala b/runner/src/mill/runner/MillBuildRootModule.scala
index f0974754fa9..3155785e9d3 100644
--- a/runner/src/mill/runner/MillBuildRootModule.scala
+++ b/runner/src/mill/runner/MillBuildRootModule.scala
@@ -4,7 +4,7 @@ import coursier.Repository
 import mill._
 import mill.api.{PathRef, Result, internal}
 import mill.define.{Discover, Task}
-import mill.scalalib.{BoundDep, Dep, DepSyntax, Lib, ScalaModule}
+import mill.scalalib.{Dep, DepSyntax, Lib, ScalaModule}
 import mill.util.CoursierSupport
 import mill.util.Util.millProjectModule
 import mill.scalalib.api.Versions
@@ -41,7 +41,7 @@ class MillBuildRootModule()(implicit
   override def millSourcePath = millBuildRootModuleInfo.projectRoot / os.up / "mill-build"
   override def intellijModulePath: os.Path = millSourcePath / os.up
 
-  override def scalaVersion: T[String] = "2.13.10"
+  override def scalaVersion: T[String] = BuildInfo.scalaVersion
 
   /**
    * All script files (that will get wrapped later)