diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 1ea336c4c0d1..20b59eb56aa6 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -360,12 +360,9 @@ jobs:
       - name: Add SBT proxy repositories
         run: cp -vf .github/workflows/repositories /root/.sbt/ ; true
 
-      - name: Test sbt 1.4.x
+      - name: Test sbt
         run: ./project/scripts/sbt "sbt-dotty/scripted; sbt-community-build/scripted"
 
-      - name: Test sbt 1.5.x
-        run: ./project/scripts/sbt "set \`sbt-dotty\`/scriptedSbt := \"1.5.0-RC1\"; sbt-dotty/scripted sbt-dotty/*"
-
   test_java8:
     runs-on: [self-hosted, Linux]
     container:
diff --git a/community-build/community-projects/stdLib213 b/community-build/community-projects/stdLib213
index d39b0169e2e1..891f92f01cfb 160000
--- a/community-build/community-projects/stdLib213
+++ b/community-build/community-projects/stdLib213
@@ -1 +1 @@
-Subproject commit d39b0169e2e1fa434d05669fe4abc720ac879e6e
+Subproject commit 891f92f01cfbc900a1a1efada73530246babd075
diff --git a/community-build/src/scala/dotty/communitybuild/projects.scala b/community-build/src/scala/dotty/communitybuild/projects.scala
index a44b44d6085f..b1433492a00c 100644
--- a/community-build/src/scala/dotty/communitybuild/projects.scala
+++ b/community-build/src/scala/dotty/communitybuild/projects.scala
@@ -102,12 +102,12 @@ final case class SbtCommunityProject(
     scalacOptions.map("\"" + _ + "\"").mkString("List(", ",", ")")
 
   private val baseCommand =
-    "clean; set logLevel in Global := Level.Error; set updateOptions in Global ~= (_.withLatestSnapshots(false)); "
-    ++ (if scalacOptions.isEmpty then "" else s"""set scalacOptions in Global ++= $scalacOptionsString;""")
+    "clean; set Global/logLevel := Level.Error; set Global/updateOptions ~= (_.withLatestSnapshots(false)); "
+    ++ (if scalacOptions.isEmpty then "" else s"""set Global/scalacOptions ++= $scalacOptionsString;""")
     ++ s"++$compilerVersion!; "
 
   override val testCommand =
-    """set testOptions in Global += Tests.Argument(TestFramework("munit.Framework"), "+l"); """
+    """set Global/testOptions += Tests.Argument(TestFramework("munit.Framework"), "+l"); """
     ++ s"$baseCommand$sbtTestCommand"
 
   override val publishCommand =
@@ -124,7 +124,7 @@ final case class SbtCommunityProject(
       case Some(ivyHome) => List(s"-Dsbt.ivy.home=$ivyHome")
       case _ => Nil
     extraSbtArgs ++ sbtProps ++ List(
-      "-sbt-version", "1.4.9",
+      "-sbt-version", "1.5.0",
       "-Dsbt.supershell=false",
       s"-Ddotty.communitybuild.dir=$communitybuildDir",
       s"--addPluginSbtFile=$sbtPluginFilePath"
@@ -140,12 +140,12 @@ object projects:
 
   private def forceDoc(projects: String*) =
     projects.map(project =>
-      s""";set $project/Compile/doc/sources ++= ($project/Compile/doc/tastyFiles).value ;$project/doc"""
+      s""";set $project/Compile/doc/sources ++= ($project/Compile/doc/dotty.tools.sbtplugin.DottyPlugin.autoImport.tastyFiles).value ;$project/doc"""
     ).mkString(" ")
 
   private def aggregateDoc(in: String)(projects: String*) =
     val tastyFiles =
-      (in +: projects).map(p => s"($p/Compile/doc/tastyFiles).value").mkString(" ++ ")
+      (in +: projects).map(p => s"($p/Compile/doc/dotty.tools.sbtplugin.DottyPlugin.autoImport.tastyFiles).value").mkString(" ++ ")
     s""";set $in/Compile/doc/sources ++= file("a.scala") +: ($tastyFiles) ;$in/doc"""
 
   lazy val utest = MillCommunityProject(
@@ -512,7 +512,7 @@ object projects:
 
   lazy val cats = SbtCommunityProject(
     project = "cats",
-    sbtTestCommand = "set scalaJSStage in Global := FastOptStage;buildJVM;validateAllJS",
+    sbtTestCommand = "set Global/scalaJSStage := FastOptStage;buildJVM;validateAllJS",
     sbtPublishCommand = "catsJVM/publishLocal;catsJS/publishLocal",
     dependencies = List(discipline, disciplineMunit, scalacheck, simulacrumScalafixAnnotations),
     scalacOptions = SbtCommunityProject.scalacOptions.filter(_ != "-Ysafe-init") // disable -Ysafe-init, due to -Xfatal-warning
diff --git a/project/Build.scala b/project/Build.scala
index e06f260a581b..f8c2866a6acb 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -1248,6 +1248,9 @@ object Build {
         baseDirectory.value / "../language-server/src/dotty/tools/languageserver/config",
       sbtTestDirectory := baseDirectory.value / "sbt-test",
 
+      // ensure that sbt-dotty is built on sbt 1.4
+      pluginCrossBuild / sbtVersion := "1.4.9",
+
       // The batch mode accidentally became the default with no way to disable
       // it in sbt 1.4 (https://github.com/sbt/sbt/issues/5913#issuecomment-716003195).
       // We enable it explicitly here to make it clear that we're using it.
diff --git a/project/build.properties b/project/build.properties
index dbae93bcfd51..e67343ae796c 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.4.9
+sbt.version=1.5.0