diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4ca1c91..a2852d1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -45,7 +45,7 @@ jobs:
     - uses: sbt/setup-sbt@v1
     - run: sbt -v test
     - run: |
-        sbt -v publishLocal "project plugin" "^ scripted" &&
+        sbt -v publishLocal plugin2_12/scripted plugin3/scripted &&
         java -jar ./target/scala-2.11/proguard/conscript-*.jar --version
   push_gh_pages:
     needs: [test, setup_script_unix, setup_script_windows]
diff --git a/build.sbt b/build.sbt
index 10f5b06..aabbec7 100644
--- a/build.sbt
+++ b/build.sbt
@@ -29,7 +29,6 @@ lazy val commonSettings = Seq(
         Seq("-language:_", "-Xlint", "-Xfuture")
     }
   },
-  crossSbtVersions := Seq("1.2.8")
 )
 
 lazy val root = (project in file(".")).
@@ -86,12 +85,12 @@ lazy val root = (project in file(".")).
       inquireVersions,
       runClean,
       runTest,
-      releaseStepCommandAndRemaining(s"^ plugin/scripted"),
+      releaseStepCommandAndRemaining(s"plugin2_12/scripted ; plugin3/scripted "),
       setReleaseVersion,
       releaseStepTask(updateLaunchconfig),
       commitReleaseVersion,
       tagRelease,
-      releaseStepCommandAndRemaining(s";publishSigned;^ plugin/publishSigned"),
+      releaseStepCommandAndRemaining(s";publishSigned; plugin2_12/publishSigned; plugin3/publishSigned"),
       releaseStepCommandAndRemaining("sonaRelease"),
       setNextVersion,
       commitNextVersion,
@@ -170,10 +169,19 @@ lazy val javaVmArgs: List[String] = {
   java.lang.management.ManagementFactory.getRuntimeMXBean.getInputArguments.asScala.toList
 }
 
-lazy val plugin = (project in file("sbt-conscript")).
-  enablePlugins(SbtPlugin).
-  settings(
+lazy val plugin = (projectMatrix in file("sbt-conscript"))
+  .jvmPlatform(scalaVersions = Seq("3.7.2", "2.12.20"))
+  .enablePlugins(SbtPlugin)
+  .settings(
     commonSettings,
+    pluginCrossBuild / sbtVersion := {
+      scalaBinaryVersion.value match {
+        case "2.12" =>
+          "1.2.8"
+        case _ =>
+          "2.0.0-RC3"
+      }
+    },
     buildInfo(packageName = "sbtconscript", v = Dependencies.launcherInterface.revision),
     name := "sbt-conscript",
     scriptedBufferLog := false,
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 4636b51..cccaf0b 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,3 +1,4 @@
+addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.11.0")
 addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("com.github.sbt" % "sbt-release" % "1.4.0")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.13.1")
diff --git a/sbt-conscript/src/main/scala-2/ConscriptPluginCompat.scala b/sbt-conscript/src/main/scala-2/ConscriptPluginCompat.scala
new file mode 100644
index 0000000..179a1c3
--- /dev/null
+++ b/sbt-conscript/src/main/scala-2/ConscriptPluginCompat.scala
@@ -0,0 +1,9 @@
+package sbtconscript
+
+import java.io.File
+import java.net.URL
+
+private[sbtconscript] object ConscriptPluginCompat {
+  def toURL(u: URL): URL = u
+  def toClasspath(f: File): File = f
+}
diff --git a/sbt-conscript/src/main/scala-3/ConscriptPluginCompat.scala b/sbt-conscript/src/main/scala-3/ConscriptPluginCompat.scala
new file mode 100644
index 0000000..55ea925
--- /dev/null
+++ b/sbt-conscript/src/main/scala-3/ConscriptPluginCompat.scala
@@ -0,0 +1,11 @@
+package sbtconscript
+
+import java.io.File
+import java.net.URL
+import java.net.URI
+import java.nio.file.Path
+
+private[sbtconscript] object ConscriptPluginCompat {
+  def toURL(u: URI): URL = u.toURL
+  def toClasspath(f: File): Path = f.toPath
+}
diff --git a/sbt-conscript/src/main/scala/ConscriptPlugin.scala b/sbt-conscript/src/main/scala/ConscriptPlugin.scala
index 102e81a..034ce03 100644
--- a/sbt-conscript/src/main/scala/ConscriptPlugin.scala
+++ b/sbt-conscript/src/main/scala/ConscriptPlugin.scala
@@ -8,6 +8,7 @@ object ConscriptPlugin extends AutoPlugin {
   override lazy val requires = plugins.JvmPlugin
   object autoImport {
     lazy val csBoot = settingKey[File]("Boot directory used by csRun")
+    @transient
     lazy val csWrite = taskKey[Unit]("Write test launchconfig files to conscript-output")
     lazy val csRun = inputKey[Unit]("Run a named launchconfig, with parameters")
     lazy val csSbtLauncherVersion = settingKey[String]("sbt launcher version")
@@ -64,14 +65,14 @@ object ConscriptPlugin extends AutoPlugin {
     val launcherFile = conscriptHome / launcher
     if(!launcherFile.exists) {
       val u = url(s"https://repo1.maven.org/maven2/org/scala-sbt/launcher/$launcherVersion/launcher-$launcherVersion.jar")
-      sbt.io.Using.urlInputStream(u) { inputStream =>
+      sbt.io.Using.urlInputStream(ConscriptPluginCompat.toURL(u)) { inputStream =>
         IO.transfer(inputStream, launcherFile)
       }
     }
     val f = new sbt.ForkRun(ForkOptions())
     f.run(
       mainClass = "xsbt.boot.Boot",
-      classpath = launcherFile :: Nil,
+      classpath = ConscriptPluginCompat.toClasspath(launcherFile) :: Nil,
       options = ("@" + config.toString) :: args.toList.tail,
       log = streams.value.log
     )