diff --git a/sbt-app/src/sbt-test/actions/configuration-delegation/build.sbt b/sbt-app/src/sbt-test/actions/configuration-delegation/build.sbt
index bc45e0058..9cd20a168 100644
--- a/sbt-app/src/sbt-test/actions/configuration-delegation/build.sbt
+++ b/sbt-app/src/sbt-test/actions/configuration-delegation/build.sbt
@@ -2,7 +2,7 @@ lazy val foo = taskKey[Unit]("Runs the foo task")
 
 lazy val bar = taskKey[Unit]("Runs the bar task")
 
-def makeFoo(config: Configuration): Setting[_] = 
+def makeFoo(config: Configuration): Setting[?] = 
   config / foo := IO.write(file(s"${config.name}-foo"), "foo")
 
 lazy val PerformanceTest = (config("pt") extend Test)
diff --git a/sbt-app/src/sbt-test/actions/reload/log-in-setting.sbt b/sbt-app/src/sbt-test/actions/reload/log-in-setting.sbt
index a7b7b12cc..8284d421c 100644
--- a/sbt-app/src/sbt-test/actions/reload/log-in-setting.sbt
+++ b/sbt-app/src/sbt-test/actions/reload/log-in-setting.sbt
@@ -9,7 +9,7 @@ TaskKey[Unit]("evil-clear-logger") := Def.uncached {
   val cls = logger.getClass
   val field = cls.getDeclaredField("ref")
   field.setAccessible(true)
-  val ref = field.get(logger).asInstanceOf[java.lang.ref.WeakReference[_]]
+  val ref = field.get(logger).asInstanceOf[java.lang.ref.WeakReference[?]]
   // MUHAHAHHAHAHAHAHHAHA, I am de evil GC, I clear things.
   ref.clear()
 }
\ No newline at end of file
diff --git a/sbt-app/src/sbt-test/actions/set/build.sbt b/sbt-app/src/sbt-test/actions/set/build.sbt
index d4b9dd7c4..f8a1ac717 100644
--- a/sbt-app/src/sbt-test/actions/set/build.sbt
+++ b/sbt-app/src/sbt-test/actions/set/build.sbt
@@ -13,7 +13,7 @@ TaskKey[Unit]("evil-clear-logger") := Def.uncached {
   val cls = logger.getClass
   val field = cls.getDeclaredField("ref")
   field.setAccessible(true)
-  val ref = field.get(logger).asInstanceOf[java.lang.ref.WeakReference[_]]
+  val ref = field.get(logger).asInstanceOf[java.lang.ref.WeakReference[?]]
   // MUHAHAHHAHAHAHAHHAHA, I am de evil GC, I clear things.
   ref.clear()
   ()
diff --git a/sbt-app/src/sbt-test/actions/state/build.sbt b/sbt-app/src/sbt-test/actions/state/build.sbt
index ecad0f931..7433c3c01 100644
--- a/sbt-app/src/sbt-test/actions/state/build.sbt
+++ b/sbt-app/src/sbt-test/actions/state/build.sbt
@@ -44,7 +44,7 @@ def persistedSetting = persist := (loadPrevious(persist) map { case None => 17;
 def  inMemoryCheck = checkKeep    := (inputCheck( (ctx, s) => Space ~> str( getFromContext(   keep, ctx, s)) )).evaluated
 def persistedCheck = checkPersist := (inputCheck( (ctx, s) => Space ~> str(loadFromContext(persist, ctx, s)) )).evaluated
 
-def inputCheck[T](f: (ScopedKey[_], State) => Parser[T]): Initialize[InputTask[Unit]] =
+def inputCheck[T](f: (ScopedKey[?], State) => Parser[T]): Initialize[InputTask[Unit]] =
   InputTask.separate( resolvedScoped(ctx => (s: State) => f(ctx, s)) )( dummyTask )
 
 import sbt.TupleSyntax.*
diff --git a/sbt-app/src/sbt-test/dependency-management/chainresolver/build.sbt b/sbt-app/src/sbt-test/dependency-management/chainresolver/build.sbt
index 6e54bdb5c..7c3830b8d 100644
--- a/sbt-app/src/sbt-test/dependency-management/chainresolver/build.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/chainresolver/build.sbt
@@ -5,7 +5,7 @@ ThisBuild / csrCacheDirectory := (ThisBuild / baseDirectory).value / "coursier-c
 def localCache =
   ivyPaths := IvyPaths(baseDirectory.value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
 
-def commonSettings: Seq[Def.Setting[_]] =
+def commonSettings: Seq[Def.Setting[?]] =
   Seq(
     localCache,
     ThisBuild / scalaVersion := "2.11.12",
diff --git a/sbt-app/src/sbt-test/dependency-management/circular-dependency/changes/multi.sbt b/sbt-app/src/sbt-test/dependency-management/circular-dependency/changes/multi.sbt
index 761ca9dd0..9179a8e41 100644
--- a/sbt-app/src/sbt-test/dependency-management/circular-dependency/changes/multi.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/circular-dependency/changes/multi.sbt
@@ -5,7 +5,7 @@ lazy val check = taskKey[Unit]("Runs the check")
 def localCache =
   ivyPaths := IvyPaths(baseDirectory.value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
 
-def commonSettings: Seq[Def.Setting[_]] =
+def commonSettings: Seq[Def.Setting[?]] =
   Seq(
     localCache,
     scalaVersion := "2.10.4",
diff --git a/sbt-app/src/sbt-test/dependency-management/circular-dependency/multi.sbt b/sbt-app/src/sbt-test/dependency-management/circular-dependency/multi.sbt
index 21a3a8acd..62ed3af48 100644
--- a/sbt-app/src/sbt-test/dependency-management/circular-dependency/multi.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/circular-dependency/multi.sbt
@@ -5,7 +5,7 @@ ThisBuild / csrCacheDirectory := (ThisBuild / baseDirectory).value / "coursier-c
 def localCache =
   ivyPaths := IvyPaths(baseDirectory.value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
 
-def commonSettings: Seq[Def.Setting[_]] =
+def commonSettings: Seq[Def.Setting[?]] =
   Seq(
     localCache,
     scalaVersion := "2.10.4",
diff --git a/sbt-app/src/sbt-test/dependency-management/evicted-semver-spec/build.sbt b/sbt-app/src/sbt-test/dependency-management/evicted-semver-spec/build.sbt
index 7f007ae81..882434a86 100644
--- a/sbt-app/src/sbt-test/dependency-management/evicted-semver-spec/build.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/evicted-semver-spec/build.sbt
@@ -4,7 +4,7 @@ ThisBuild / scalaVersion := "2.13.12"
 ThisBuild / versionScheme := Some("semver-spec")
 ThisBuild / csrCacheDirectory := (ThisBuild / baseDirectory).value / "coursier-cache"
 
-def commonSettings: Seq[Def.Setting[_]] =
+def commonSettings: Seq[Def.Setting[?]] =
   Seq(
     fullResolvers := Def.uncached(fullResolvers.value.filterNot(_.name == "inter-project")),
     publishTo := Some(MavenCache("local-maven", (LocalRootProject / target).value / "local-maven")),
diff --git a/sbt-app/src/sbt-test/dependency-management/gh-1484-npe/build.sbt b/sbt-app/src/sbt-test/dependency-management/gh-1484-npe/build.sbt
index f876295d2..dd5731609 100644
--- a/sbt-app/src/sbt-test/dependency-management/gh-1484-npe/build.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/gh-1484-npe/build.sbt
@@ -1,6 +1,6 @@
 lazy val check = taskKey[Unit]("tests update")
 
-def commonSettings: Seq[Def.Setting[_]] = Seq(
+def commonSettings: Seq[Def.Setting[?]] = Seq(
     resolvers ++= Vector(Resolver.typesafeIvyRepo("releases"), Resolver.typesafeRepo("releases"), Resolver.sbtPluginRepo("releases")),
     check := {
       val ur = update.value
diff --git a/sbt-app/src/sbt-test/dependency-management/mvn-local/build.sbt b/sbt-app/src/sbt-test/dependency-management/mvn-local/build.sbt
index b0a72691b..fea60fb80 100644
--- a/sbt-app/src/sbt-test/dependency-management/mvn-local/build.sbt
+++ b/sbt-app/src/sbt-test/dependency-management/mvn-local/build.sbt
@@ -1,6 +1,6 @@
 ThisBuild / csrCacheDirectory := (ThisBuild / baseDirectory).value / "coursier-cache"
 
-def commonSettings: Seq[Def.Setting[_]] =
+def commonSettings: Seq[Def.Setting[?]] =
   Seq(
     ivyPaths := IvyPaths( (ThisBuild / baseDirectory).value, Some((baseDirectory in LocalRootProject).value / "ivy-cache")),
     dependencyCacheDirectory := (baseDirectory in LocalRootProject).value / "dependency",
diff --git a/sbt-app/src/sbt-test/ivy-deps-management/update-classifiers-snapshot-srcs/build.sbt b/sbt-app/src/sbt-test/ivy-deps-management/update-classifiers-snapshot-srcs/build.sbt
index fbd3c5f71..20b16f73c 100644
--- a/sbt-app/src/sbt-test/ivy-deps-management/update-classifiers-snapshot-srcs/build.sbt
+++ b/sbt-app/src/sbt-test/ivy-deps-management/update-classifiers-snapshot-srcs/build.sbt
@@ -3,7 +3,7 @@ def localRepo = Def.setting((target in LocalRootProject).value / "local-repo")
 
 ThisBuild / csrCacheDirectory := (ThisBuild / baseDirectory).value / "coursier-cache"
 
-val commonSettings = Seq[Def.Setting[_]](
+val commonSettings = Seq[Def.Setting[?]](
   organization := "org.example",
   version := "1.0-SNAPSHOT",
   scalaVersion := "2.11.7",
diff --git a/sbt-app/src/sbt-test/nio/transform/build.sbt b/sbt-app/src/sbt-test/nio/transform/build.sbt
index 9aba3478f..53c8d35fe 100644
--- a/sbt-app/src/sbt-test/nio/transform/build.sbt
+++ b/sbt-app/src/sbt-test/nio/transform/build.sbt
@@ -15,7 +15,7 @@ transform := {
   StateTransform(_.put(foo, 1))
 }
 
-def inputCheck[T](f: (ScopedKey[_], State) => Parser[T]): Initialize[InputTask[Unit]] =
+def inputCheck[T](f: (ScopedKey[?], State) => Parser[T]): Initialize[InputTask[Unit]] =
   InputTask(resolvedScoped(ctx => (s: State) => f(ctx, s)))(dummyTask)
 
 val checkTransform = taskKey[Unit]("")
diff --git a/sbt-app/src/sbt-test/project-matrix/projectAxes/build.sbt b/sbt-app/src/sbt-test/project-matrix/projectAxes/build.sbt
index 87667c258..956fc9c2f 100644
--- a/sbt-app/src/sbt-test/project-matrix/projectAxes/build.sbt
+++ b/sbt-app/src/sbt-test/project-matrix/projectAxes/build.sbt
@@ -39,7 +39,7 @@ lazy val custom =
   )
 
 
-lazy val platformSettings = Seq[Def.Setting[_]](
+lazy val platformSettings = Seq[Def.Setting[?]](
     platformTest := {
       if(virtualAxes.value.contains(sbt.VirtualAxis.js)) "js-platform"
       else if(virtualAxes.value.contains(sbt.VirtualAxis.jvm)) "jvm-platform"
@@ -47,7 +47,7 @@ lazy val platformSettings = Seq[Def.Setting[_]](
     }
 )
 
-lazy val customSettings = Seq[Def.Setting[_]](
+lazy val customSettings = Seq[Def.Setting[?]](
   configTest := {
     if(virtualAxes.value.contains(config12)) "config for 1.2"
     else if (virtualAxes.value.contains(config13)) "config for 1.3"
diff --git a/sbt-app/src/sbt-test/reporter/command-progress/build.sbt b/sbt-app/src/sbt-test/reporter/command-progress/build.sbt
index 81985c63a..b1001eda3 100644
--- a/sbt-app/src/sbt-test/reporter/command-progress/build.sbt
+++ b/sbt-app/src/sbt-test/reporter/command-progress/build.sbt
@@ -15,8 +15,8 @@ commandProgress += new ExecuteProgress2:
       allDeps: Iterable[TaskId[?]],
       pendingDeps: Iterable[TaskId[?]]
   ): Unit = ()
-  override def afterReady(task: TaskId[_]): Unit = ()
-  override def beforeWork(task: TaskId[_]): Unit = ()
+  override def afterReady(task: TaskId[?]): Unit = ()
+  override def beforeWork(task: TaskId[?]): Unit = ()
   override def afterWork[A](task: TaskId[A], result: Either[TaskId[A], Result[A]]): Unit = ()
   override def afterCompleted[A](task: TaskId[A], result: Result[A]): Unit = ()
   override def afterAllCompleted(results: RMap[TaskId, Result]): Unit = ()