diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ece40425..aa5a0c6a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -14,7 +14,7 @@ jobs:
   build:
     strategy:
       matrix:
-        scalaVersion: ["2.13.11", "3.3.1"]
+        scalaVersion: ["2.13.12", "3.3.1"]
     runs-on: ubuntu-22.04
 
     steps:
@@ -44,7 +44,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04]
-        scala: [2.13.11]
+        scala: [2.13.12]
         java: [adopt@1.8]
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/build.sbt b/build.sbt
index ce65426d..74e81ca7 100644
--- a/build.sbt
+++ b/build.sbt
@@ -27,8 +27,8 @@ inThisBuild(
 )
 
 lazy val commonSettings = Seq(
-  crossScalaVersions := Seq("2.13.11", "3.3.1"),
-  scalaVersion       := "2.13.11",
+  crossScalaVersions := Seq("2.13.12", "3.3.1"),
+  scalaVersion       := "2.13.12",
   libraryDependencies ++= (CrossVersion.partialVersion(scalaVersion.value) match {
     case Some((3, _)) => Seq.empty
     case _            =>
@@ -110,7 +110,7 @@ lazy val rx = project
   .settings(commonSettings)
   .settings(
     name               := "colibri-rx",
-    crossScalaVersions := Seq("2.13.11"), // no scala3, because scala.rx uses scala2 macros
+    crossScalaVersions := Seq("2.13.12"), // no scala3, because scala.rx uses scala2 macros
     libraryDependencies ++= Seq(
       "com.lihaoyi" %% "scalarx" % "0.4.3",
     ),
diff --git a/reactive/src/main/scala/colibri/reactive/Reactive.scala b/reactive/src/main/scala/colibri/reactive/Reactive.scala
index 72397ba6..74eed9b2 100644
--- a/reactive/src/main/scala/colibri/reactive/Reactive.scala
+++ b/reactive/src/main/scala/colibri/reactive/Reactive.scala
@@ -9,6 +9,7 @@ import monocle.{Iso, Lens, Prism}
 import scala.concurrent.Future
 import scala.reflect.ClassTag
 import scala.util.control.NonFatal
+import scala.annotation.unused
 
 object RxMissingNowException
     extends Exception(
@@ -395,9 +396,9 @@ private final class RxConst[A](value: A) extends Rx[A] {
 
   val observable: Observable[A] = Observable.pure(value)
 
-  def apply()(implicit owner: LiveOwner): A = value
-  def now()(implicit owner: NowOwner): A    = value
-  def nowIfSubscribedOption(): Option[A]    = someValue
+  def apply()(implicit @unused owner: LiveOwner): A = value
+  def now()(implicit @unused owner: NowOwner): A    = value
+  def nowIfSubscribedOption(): Option[A]            = someValue
 }
 
 private final class RxSyncObservable[A](inner: Observable[A]) extends Rx[A] {
@@ -473,9 +474,9 @@ private final class VarSubject[A](seed: A) extends Var[A] {
   val observable: Observable[A] = state.distinctOnEquals
   def observer: Observer[A]     = state
 
-  def apply()(implicit owner: LiveOwner) = owner.unsafeLive(this)
-  def now()(implicit owner: NowOwner)    = state.now()
-  def nowIfSubscribedOption()            = Some(state.now())
+  def apply()(implicit owner: LiveOwner)      = owner.unsafeLive(this)
+  def now()(implicit @unused owner: NowOwner) = state.now()
+  def nowIfSubscribedOption()                 = Some(state.now())
 }
 
 private final class VarCreateStateless[A](innerWrite: RxWriter[A], innerRead: Rx[A]) extends Var[A] {