diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 450503e..fd048b3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,41 +1,13 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  push:
+    branches: [ master ]
+  pull_request:
 
 jobs:
   test:
-
-    runs-on: ubuntu-latest
-
-    strategy:
-      matrix:
-        scala:
-          - 2.13.5
-          - 2.12.13
-
-    steps:
-      - uses: actions/checkout@v2
-
-      - uses: coursier/cache-action@v5
-
-      - name: scala
-        uses: olafurpg/setup-scala@v10
-        with:
-          java-version: openjdk@1.11
-
-      - name: build ${{ matrix.scala }}
-        run: sbt ++${{ matrix.scala }} clean coverage test
-
-      - name: test coverage
-        if: success()
-        env:
-          COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
-        run: sbt ++${{ matrix.scala }} coverageReport coverageAggregate coveralls
-
-      - name: slack
-        uses: homoluctus/slatify@master
-        if: failure() && github.ref == 'refs/heads/master'
-        with:
-          type: ${{ job.status }}
-          job_name: Build
-          url: ${{ secrets.SLACK_WEBHOOK }}
\ No newline at end of file
+    uses: evolution-gaming/scala-github-actions/.github/workflows/ci.yml@dde27b9bd793d41d5aacf8fb74403c9de5da1146 # v6.3.0
+    # TODO remove after first release with Scala 3 support
+    with:
+      version_policy_check: false
\ No newline at end of file
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a8a2f2b..3b7a7cc 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -1,11 +1,11 @@
-name: Publish new Release
+name: Publish Release
 
 on:
-  release:
-    types: [published]
-    branches: [master]
+  push:
+    tags:
+      - 'v*'
 
 jobs:
   release:
-    uses: evolution-gaming/scala-github-actions/.github/workflows/release.yml@v1
+    uses: evolution-gaming/scala-github-actions/.github/workflows/release.yml@v5
     secrets: inherit
diff --git a/.scalafmt.conf b/.scalafmt.conf
new file mode 100644
index 0000000..d31bdbb
--- /dev/null
+++ b/.scalafmt.conf
@@ -0,0 +1,96 @@
+# Main goals:
+# - nicer commit diffs (trailing commas, no alignment for pattern matching, force new lines)
+# - better interop with default IntelliJ IDEA setup (matching import and modifiers sorting logic)
+# - better developer experience on laptop screens (like 16' MBPs) with IntelliJ IDEA (line wraps)
+
+version = 3.11.5
+
+runner.dialect = scala213source3
+
+# only format files tracked by git
+project.git = true
+
+maxColumn = 120
+trailingCommas = always
+
+preset = default
+# do not align to make nicer commit diffs
+align.preset = none
+
+indent {
+  # altering defnSite and extendSite to have this:
+  #   final class MyErr extends RuntimeException(
+  #     "super error message",
+  #   )
+  # instead of this:
+  #   final class MyErr extends RuntimeException(
+  #       "super error message",
+  #     )
+  defnSite = 2
+  extendSite = 0
+}
+
+spaces {
+  # makes string interpolation with curlies more visually distinct
+  inInterpolatedStringCurlyBraces = true
+}
+
+newlines {
+  # keep author new lines where possible
+  source = keep
+  # force new line after "(implicit" for multi-line arg lists
+  implicitParamListModifierForce = [after]
+  avoidForSimpleOverflow = [
+    tooLong, # if the line would be too long even after newline inserted, do nothing
+    slc, # do nothing if overflow caused by single line comment
+  ]
+}
+
+verticalMultiline {
+  atDefnSite = true
+  arityThreshold = 4 # more than 3 args in a list will be turned vertical
+  newlineAfterOpenParen = true # for nicer commit diffs
+}
+
+# for nicer commit diffs - forces new line before last parenthesis:
+#   class MyCls(
+#     arg1: String,
+#     arg2: String,
+#   ) extends MyTrait {
+#
+# without it:
+#   class MyCls(
+#     arg1: String,
+#     arg2: String) extends MyTrait {
+danglingParentheses.exclude = []
+
+docstrings {
+  # easier to view diffs in IDEA on 16' MBP screen if docs max line are shorter than code
+  wrapMaxColumn = 100
+  # next settings make it similar to the default IDEA javadoc formatting
+  style = Asterisk
+  oneline = unfold
+  blankFirstLine = unfold
+}
+
+rewrite.rules = [
+  Imports,
+  RedundantParens,
+  SortModifiers,
+  prefercurlyfors,
+]
+
+# put visibility modifier first
+rewrite.sortModifiers.preset = styleGuide
+
+# Import sorting as similar as possible to scalafix's "OrganizeImports.preset = INTELLIJ_2020_3".
+# Scalafix is not used as its commands mess up "all .." build aliases and it takes long time to run,
+# while its code semantic based features are not needed here.
+# I.e. detection of unused imports is done with Scala compiler options.
+rewrite.imports {
+  sort = ascii
+  groups = [
+    [".*"],
+    ["java\\..*", "javax\\..*", "scala\\..*"],
+  ]
+}
diff --git a/build.sbt b/build.sbt
index f9e98c4..08db6f9 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,33 +1,72 @@
+import sbtversionpolicy.Compatibility.BinaryCompatible
+
 name := "serially"
 
 organization := "com.evolutiongaming"
 
-homepage := Some(url("https://github.com/evolution-gaming/serially"))
+homepage := Some(uri("https://github.com/evolution-gaming/serially"))
 
 startYear := Some(2018)
 
 organizationName := "Evolution"
 
-organizationHomepage := Some(url("https://evolution.com"))
+organizationHomepage := Some(uri("https://evolution.com"))
 
 scalaVersion := crossScalaVersions.value.head
 
-crossScalaVersions := Seq("2.13.5", "2.12.13")
+crossScalaVersions := Seq("2.13.18", "3.3.8")
+
+scalacOptions ++= crossSettings(
+  scalaVersion = scalaVersion.value,
+  // Good compiler options for Scala 2.13 are coming from com.evolution:sbt-scalac-opts-plugin:0.1.0,
+  // but its support for Scala 3 is limited, especially what concerns linting options.
+  //
+  // If Scala 3 is made the primary target, good linting scalac options for it should be added first.
+  if3 = Seq(
+    "-Ykind-projector:underscores",
+
+    // disable new brace-less syntax:
+    // https://alexn.org/blog/2022/10/24/scala-3-optional-braces/
+    "-no-indent",
+
+    // improve error messages:
+    "-explain",
+    "-explain-types",
+  ),
+  if2 = Seq(
+    "-Xsource:3",
+  ),
+)
 
 Compile / doc / scalacOptions ++= Seq("-groups", "-implicits", "-no-link-warnings")
 
 publishTo := Some(Resolver.evolutionReleases)
 
+versionPolicyIntention := BinaryCompatible
+
 libraryDependencies ++= Seq(
-  "com.evolutiongaming" %% "future-helper" % "1.0.6",
-  "com.typesafe.akka"   %% "akka-actor"    % "2.6.8",
-  "com.typesafe.akka"   %% "akka-testkit"  % "2.6.8" % Test,
-  "org.scalatest"       %% "scalatest"     % "3.2.9"  % Test)
+  "com.evolutiongaming" %% "future-helper" % "1.0.7",
+  "com.typesafe.akka" %% "akka-actor" % "2.6.21", // scala-steward:off
+  "com.typesafe.akka" %% "akka-testkit" % "2.6.21" % Test, // scala-steward:off
+  "org.scalatest" %% "scalatest" % "3.2.20" % Test,
+)
+
+// TODO remove after first release with Scala 3 support
+versionPolicyIgnored ++= Seq(
+  // add libraries here that are known to be binary compatible, like:
+  "com.typesafe.akka" %% "akka-actor",
+  "org.scala-lang.modules" %% "scala-java8-compat",
+)
 
-licenses := Seq(("MIT", url("https://opensource.org/licenses/MIT")))
+licenses := Seq(("MIT", uri("https://opensource.org/licenses/MIT")))
 
-releaseCrossBuild := true
+def crossSettings[T](scalaVersion: String, if3: T, if2: T): T = {
+  scalaVersion match {
+    case version if version.startsWith("3") => if3
+    case _ => if2
+  }
+}
 
-//addCommandAlias("check", "all versionPolicyCheck Compile/doc")
-addCommandAlias("check", "show version")
-addCommandAlias("build", "+all compile test")
+addCommandAlias("check", "+all scalafmtCheckRepo versionPolicyCheck Compile/doc")
+addCommandAlias("fmt", "+all scalafmtRepo")
+addCommandAlias("build", "+all compile testFull")
diff --git a/project/build.properties b/project/build.properties
index 19479ba..fdcf9af 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.5.2
+sbt.version = 2.0.6
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 8f253da..54e584d 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,9 +1,11 @@
-addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.7.2")
+addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.4.4")
 
-addSbtPlugin("org.scoverage" % "sbt-coveralls" % "1.2.7")
-
-addSbtPlugin("com.github.sbt" % "sbt-release" % "1.0.15")
+addSbtPlugin("com.github.sbt" % "sbt-dynver" % "5.1.1")
 
 addSbtPlugin("com.evolution" % "sbt-scalac-opts-plugin" % "0.2.0")
 
-addSbtPlugin("com.evolution" % "sbt-artifactory-plugin" % "0.1.2")
\ No newline at end of file
+addSbtPlugin("com.evolution" % "sbt-artifactory-plugin" % "0.1.2")
+
+addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "3.3.0")
+
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.6.2")
diff --git a/src/main/scala/com/evolutiongaming/concurrent/serially/AsyncVar.scala b/src/main/scala/com/evolutiongaming/concurrent/serially/AsyncVar.scala
index 089fee3..4207a87 100644
--- a/src/main/scala/com/evolutiongaming/concurrent/serially/AsyncVar.scala
+++ b/src/main/scala/com/evolutiongaming/concurrent/serially/AsyncVar.scala
@@ -2,7 +2,7 @@ package com.evolutiongaming.concurrent.serially
 
 import akka.actor.ActorRefFactory
 import com.evolutiongaming.concurrent.CurrentThreadExecutionContext
-import com.evolutiongaming.concurrent.FutureHelper._
+import com.evolutiongaming.concurrent.FutureHelper.*
 
 import scala.concurrent.Future
 
@@ -15,20 +15,24 @@ trait AsyncVar[S] extends StateVar[S] {
 
 object AsyncVar {
 
-  def apply[S](state: S)(implicit factory: ActorRefFactory): AsyncVar[S] = {
+  def apply[S](
+    state: S,
+  )(implicit
+    factory: ActorRefFactory,
+  ): AsyncVar[S] = {
     val serially = SeriallyAsync()
     apply(state, serially)
   }
 
   def apply[S](state: S, serially: SeriallyAsync): AsyncVar[S] = {
 
-    implicit val ec = CurrentThreadExecutionContext
+    implicit val ec: CurrentThreadExecutionContext.type = CurrentThreadExecutionContext
 
     @volatile var s = state
 
     new AsyncVar[S] {
 
-      def value() = s
+      def value(): S = s
 
       def async[SS](f: S => Future[(S, SS)]): Future[SS] = {
         serially.async[SS] {
diff --git a/src/main/scala/com/evolutiongaming/concurrent/serially/Serially.scala b/src/main/scala/com/evolutiongaming/concurrent/serially/Serially.scala
index b0291c1..1c702b1 100644
--- a/src/main/scala/com/evolutiongaming/concurrent/serially/Serially.scala
+++ b/src/main/scala/com/evolutiongaming/concurrent/serially/Serially.scala
@@ -1,9 +1,8 @@
 package com.evolutiongaming.concurrent.serially
 
-import java.util.concurrent.atomic.AtomicBoolean
-
 import akka.actor.{Actor, ActorRef, ActorRefFactory, Props}
 
+import java.util.concurrent.atomic.AtomicBoolean
 import scala.concurrent.{Future, Promise}
 import scala.util.Try
 import scala.util.control.NoStackTrace
@@ -19,24 +18,24 @@ object Serially {
 
   private val StoppedFailure = Future.failed(Stopped)
 
-  def apply(name: Option[String] = None)(implicit factory: ActorRefFactory): Serially = {
-
-    case class Func(f: () => Unit)
-    case class StopPrepare(promise: Promise[Unit])
-    case class StopCommit(promise: Promise[Unit])
+  def apply(
+    name: Option[String] = None,
+  )(implicit
+    factory: ActorRefFactory,
+  ): Serially = {
 
     def actor() = new Actor {
       def receive: Receive = {
-        case Func(f)              => f()
+        case Func(f) => f()
         case StopPrepare(promise) => self.tell(StopCommit(promise), ActorRef.noSender)
-        case StopCommit(promise)  => promise.success(()); context.stop(self);
+        case StopCommit(promise) => promise.success(()); context.stop(self);
       }
     }
 
     val props = Props(actor())
 
     val ref = name match {
-      case None       => factory.actorOf(props)
+      case None => factory.actorOf(props)
       case Some(name) => factory.actorOf(props, name)
     }
 
@@ -61,7 +60,7 @@ object Serially {
         }
       }
 
-      def stop() = {
+      def stop(): Future[Unit] = {
         running {
           if (stopped.compareAndSet(false, true)) {
             val promise = Promise[Unit]()
@@ -75,14 +74,16 @@ object Serially {
     }
   }
 
-
   def now: Serially = new Serially {
 
     def apply[T](f: => T): Future[T] = Future.fromTry(Try(f))
 
-    def stop() = Future.unit
+    def stop(): Future[Unit] = Future.unit
   }
 
+  private case class Func(f: () => Unit)
+  private case class StopPrepare(promise: Promise[Unit])
+  private case class StopCommit(promise: Promise[Unit])
 
   case object Stopped extends RuntimeException with NoStackTrace
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/com/evolutiongaming/concurrent/serially/SeriallyAsync.scala b/src/main/scala/com/evolutiongaming/concurrent/serially/SeriallyAsync.scala
index f8208e7..bb4c6dd 100644
--- a/src/main/scala/com/evolutiongaming/concurrent/serially/SeriallyAsync.scala
+++ b/src/main/scala/com/evolutiongaming/concurrent/serially/SeriallyAsync.scala
@@ -2,7 +2,7 @@ package com.evolutiongaming.concurrent.serially
 
 import akka.actor.ActorRefFactory
 import com.evolutiongaming.concurrent.CurrentThreadExecutionContext
-import com.evolutiongaming.concurrent.FutureHelper._
+import com.evolutiongaming.concurrent.FutureHelper.*
 
 import scala.concurrent.Future
 import scala.util.{Success, Try}
@@ -18,7 +18,11 @@ trait SeriallyAsync extends Serially {
 
 object SeriallyAsync {
 
-  def apply(name: Option[String] = None)(implicit factory: ActorRefFactory): SeriallyAsync = {
+  def apply(
+    name: Option[String] = None,
+  )(implicit
+    factory: ActorRefFactory,
+  ): SeriallyAsync = {
     val serially = Serially(name)
     apply(serially)
   }
@@ -27,13 +31,13 @@ object SeriallyAsync {
 
     var future = Future.unit
 
-    implicit val ec = CurrentThreadExecutionContext
+    implicit val ec: CurrentThreadExecutionContext.type = CurrentThreadExecutionContext
     val tryUnit = Success(())
-    val tryToUnit = (_: Try[_]) => tryUnit
+    val tryToUnit = (_: Try[?]) => tryUnit
 
     new SeriallyAsync {
 
-      def async[T](f: => Future[T]) = {
+      def async[T](f: => Future[T]): Future[T] = {
         serially {
           val result = if (future.isCompleted) f else future.flatMap(_ => f)
           future = FutureOps(result).transform(tryToUnit)
@@ -41,15 +45,14 @@ object SeriallyAsync {
         }.flatten
       }
 
-      def stop() = serially.stop()
+      def stop(): Future[Unit] = serially.stop()
     }
   }
 
-
   def now: SeriallyAsync = new SeriallyAsync {
 
-    def async[T](f: => Future[T]) = f
+    def async[T](f: => Future[T]): Future[T] = f
 
-    def stop() = Future.unit
+    def stop(): Future[Unit] = Future.unit
   }
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/com/evolutiongaming/concurrent/serially/StateVar.scala b/src/main/scala/com/evolutiongaming/concurrent/serially/StateVar.scala
index 7819a43..03dbbcf 100644
--- a/src/main/scala/com/evolutiongaming/concurrent/serially/StateVar.scala
+++ b/src/main/scala/com/evolutiongaming/concurrent/serially/StateVar.scala
@@ -11,8 +11,9 @@ trait StateVar[S] {
   def apply[SS](f: S => (S, SS)): Future[SS]
 
   /**
-    * @return previous value
-    */
+   * @return
+   *   previous value
+   */
   final def set(value: S): Future[S] = getAndUpdate(_ => value)
 
   final def update(f: S => S): Future[S] = updateAndGet(f)
@@ -41,7 +42,11 @@ trait StateVar[S] {
 
 object StateVar {
 
-  def apply[S](state: S)(implicit factory: ActorRefFactory): StateVar[S] = {
+  def apply[S](
+    state: S,
+  )(implicit
+    factory: ActorRefFactory,
+  ): StateVar[S] = {
     val serially = Serially()
     apply(state, serially)
   }
@@ -52,7 +57,7 @@ object StateVar {
 
     new StateVar[S] {
 
-      def value() = s
+      def value(): S = s
 
       def apply[SS](f: S => (S, SS)): Future[SS] = {
         serially {
@@ -65,4 +70,4 @@ object StateVar {
       override def toString = s"StateVar($s)"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/test/scala/com/evolutiongaming/concurrent/serially/AsyncVarSpec.scala b/src/test/scala/com/evolutiongaming/concurrent/serially/AsyncVarSpec.scala
index 1f11ab9..0a0feba 100644
--- a/src/test/scala/com/evolutiongaming/concurrent/serially/AsyncVarSpec.scala
+++ b/src/test/scala/com/evolutiongaming/concurrent/serially/AsyncVarSpec.scala
@@ -1,16 +1,17 @@
 package com.evolutiongaming.concurrent.serially
 
-
-import scala.util.Success
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
 
+import scala.concurrent.Future
+import scala.util.Success
+
 class AsyncVarSpec extends AnyWordSpec with Matchers {
 
   "AsyncVar" should {
 
     "apply" in new Scope {
-      val result = state { before =>
+      val result: Future[Int] = state { before =>
         val after = before + 1
         (after, before)
       }
@@ -23,19 +24,19 @@ class AsyncVarSpec extends AnyWordSpec with Matchers {
     }
 
     "update" in new Scope {
-      val result = state.update(_ + 1)
+      val result: Future[Int] = state.update(_ + 1)
       result.value shouldEqual Some(Success(1))
       state.value() shouldEqual 1
     }
 
     "updateAndGet" in new Scope {
-      val result = state.updateAndGet(_ + 1)
+      val result: Future[Int] = state.updateAndGet(_ + 1)
       result.value shouldEqual Some(Success(1))
       state.value() shouldEqual 1
     }
 
     "getAndUpdate" in new Scope {
-      val result = state.getAndUpdate(_ + 1)
+      val result: Future[Int] = state.getAndUpdate(_ + 1)
       result.value shouldEqual Some(Success(0))
       state.value() shouldEqual 1
     }
@@ -47,7 +48,7 @@ class AsyncVarSpec extends AnyWordSpec with Matchers {
     }
 
     "set" in new Scope {
-      val result = state.set(1)
+      val result: Future[Int] = state.set(1)
       result.value shouldEqual Some(Success(0))
       state.value() shouldEqual 1
     }
@@ -58,7 +59,7 @@ class AsyncVarSpec extends AnyWordSpec with Matchers {
   }
 
   private trait Scope {
-    val serially = SeriallyAsync.now
+    private val serially = SeriallyAsync.now
     val state = AsyncVar(0, serially)
   }
-}
\ No newline at end of file
+}
diff --git a/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallyAsyncSpec.scala b/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallyAsyncSpec.scala
index ecff974..5fa2624 100644
--- a/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallyAsyncSpec.scala
+++ b/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallyAsyncSpec.scala
@@ -2,13 +2,12 @@ package com.evolutiongaming.concurrent.serially
 
 import com.evolutiongaming.concurrent.CurrentThreadExecutionContext
 import org.scalatest.concurrent.ScalaFutures
-
-import scala.concurrent.duration._
-import scala.concurrent.{Await, Promise, TimeoutException}
-import scala.util.control.NoStackTrace
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
 
+import scala.concurrent.duration.*
+import scala.concurrent.{Await, Future, Promise, TimeoutException}
+import scala.util.control.NoStackTrace
 
 class SeriallyAsyncSpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFutures {
 
@@ -18,7 +17,7 @@ class SeriallyAsyncSpec extends AnyWordSpec with ActorSpec with Matchers with Sc
       var value = 0
       val promise = Promise[Int]()
       serially { value = promise.future.futureValue }
-      val future = serially { value = 2 }
+      val future: Future[Unit] = serially { value = 2 }
       intercept[TimeoutException] { Await.result(future, 100.millis) }
       promise.success(1)
       Await.result(future, timeout.duration)
@@ -29,7 +28,7 @@ class SeriallyAsyncSpec extends AnyWordSpec with ActorSpec with Matchers with Sc
       var value = 0
       val promise = Promise[Int]()
       serially.async { promise.future.map(value = _)(CurrentThreadExecutionContext) }
-      val future = serially { value = 2 }
+      val future: Future[Unit] = serially { value = 2 }
       intercept[TimeoutException] { Await.result(future, 100.millis) }
       promise.success(1)
       Await.result(future, timeout.duration)
@@ -37,20 +36,20 @@ class SeriallyAsyncSpec extends AnyWordSpec with ActorSpec with Matchers with Sc
     }
 
     "not fail on exceptions" in new Scope {
-      val future1 = serially { throw TestException }
+      val future1: Future[Nothing] = serially { throw TestException }
 
       intercept[TestException.type] { Await.result(future1, timeout.duration) }
 
-      val future2 = serially { 1 }
+      val future2: Future[Int] = serially { 1 }
       Await.result(future2, timeout.duration) shouldEqual 1
     }
 
     "fail tasks when stopped" in new Scope {
       val promise = Promise[Int]()
-      val result0 = serially { promise.future.futureValue }
-      val result1 = serially { 1 }
-      val resultStop = serially.stop()
-      val result2 = serially { 2 }
+      val result0: Future[Int] = serially { promise.future.futureValue }
+      val result1: Future[Int] = serially { 1 }
+      val resultStop: Future[Unit] = serially.stop()
+      val result2: Future[Int] = serially { 2 }
 
       promise.success(0)
 
@@ -60,14 +59,14 @@ class SeriallyAsyncSpec extends AnyWordSpec with ActorSpec with Matchers with Sc
 
       intercept[Serially.Stopped.type] { Await.result(result2, timeout.duration) }
 
-      val result3 = serially { 3 }
+      val result3: Future[Int] = serially { 3 }
 
       intercept[Serially.Stopped.type] { Await.result(result3, timeout.duration) }
     }
   }
 
   private trait Scope extends ActorScope {
-    val serially = SeriallyAsync()(system)
+    val serially: SeriallyAsync = SeriallyAsync()(system)
   }
 
   case object TestException extends RuntimeException with NoStackTrace
diff --git a/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallySpec.scala b/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallySpec.scala
index 96e72be..b892e85 100644
--- a/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallySpec.scala
+++ b/src/test/scala/com/evolutiongaming/concurrent/serially/SeriallySpec.scala
@@ -1,13 +1,13 @@
 package com.evolutiongaming.concurrent.serially
 
 import org.scalatest.concurrent.ScalaFutures
-
-import scala.concurrent.duration._
-import scala.concurrent.{Await, Promise, TimeoutException}
-import scala.util.control.NoStackTrace
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
 
+import scala.concurrent.duration.*
+import scala.concurrent.{Await, Future, Promise, TimeoutException}
+import scala.util.control.NoStackTrace
+
 class SeriallySpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFutures {
 
   "Serially" should {
@@ -16,7 +16,7 @@ class SeriallySpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFu
       var value = 0
       val promise = Promise[Int]()
       serially { value = promise.future.futureValue }
-      val future = serially { value = 2 }
+      val future: Future[Unit] = serially { value = 2 }
       intercept[TimeoutException] { Await.result(future, 100.millis) }
       promise.success(1)
       Await.result(future, timeout.duration)
@@ -24,20 +24,20 @@ class SeriallySpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFu
     }
 
     "not fail on exceptions" in new Scope {
-      val future1 = serially { throw TestException }
+      val future1: Future[Nothing] = serially { throw TestException }
 
       intercept[TestException.type] { Await.result(future1, timeout.duration) }
 
-      val future2 = serially { 1 }
+      val future2: Future[Int] = serially { 1 }
       Await.result(future2, timeout.duration) shouldEqual 1
     }
 
     "fail tasks when stopped" in new Scope {
       val promise = Promise[Int]()
-      val result0 = serially { promise.future.futureValue }
-      val result1 = serially { 1 }
-      val resultStop = serially.stop()
-      val result2 = serially { 2 }
+      val result0: Future[Int] = serially { promise.future.futureValue }
+      val result1: Future[Int] = serially { 1 }
+      val resultStop: Future[Unit] = serially.stop()
+      val result2: Future[Int] = serially { 2 }
 
       promise.success(0)
 
@@ -47,7 +47,7 @@ class SeriallySpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFu
 
       intercept[Serially.Stopped.type] { Await.result(result2, timeout.duration) }
 
-      val result3 = serially { 3 }
+      val result3: Future[Int] = serially { 3 }
 
       intercept[Serially.Stopped.type] { Await.result(result3, timeout.duration) }
     }
@@ -59,4 +59,3 @@ class SeriallySpec extends AnyWordSpec with ActorSpec with Matchers with ScalaFu
 
   case object TestException extends RuntimeException with NoStackTrace
 }
-
diff --git a/src/test/scala/com/evolutiongaming/concurrent/serially/StateVarSpec.scala b/src/test/scala/com/evolutiongaming/concurrent/serially/StateVarSpec.scala
index 2dbdf54..a2363f9 100644
--- a/src/test/scala/com/evolutiongaming/concurrent/serially/StateVarSpec.scala
+++ b/src/test/scala/com/evolutiongaming/concurrent/serially/StateVarSpec.scala
@@ -1,16 +1,17 @@
 package com.evolutiongaming.concurrent.serially
 
-
-import scala.util.Success
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
 
+import scala.concurrent.Future
+import scala.util.Success
+
 class StateVarSpec extends AnyWordSpec with Matchers {
 
   "StateVar" should {
 
     "apply" in new Scope {
-      val result = state { before =>
+      val result: Future[Int] = state { before =>
         val after = before + 1
         (after, before)
       }
@@ -23,19 +24,19 @@ class StateVarSpec extends AnyWordSpec with Matchers {
     }
 
     "update" in new Scope {
-      val result = state.update(_ + 1)
+      val result: Future[Int] = state.update(_ + 1)
       result.value shouldEqual Some(Success(1))
       state.value() shouldEqual 1
     }
 
     "updateAndGet" in new Scope {
-      val result = state.updateAndGet(_ + 1)
+      val result: Future[Int] = state.updateAndGet(_ + 1)
       result.value shouldEqual Some(Success(1))
       state.value() shouldEqual 1
     }
 
     "getAndUpdate" in new Scope {
-      val result = state.getAndUpdate(_ + 1)
+      val result: Future[Int] = state.getAndUpdate(_ + 1)
       result.value shouldEqual Some(Success(0))
       state.value() shouldEqual 1
     }
@@ -47,7 +48,7 @@ class StateVarSpec extends AnyWordSpec with Matchers {
     }
 
     "set" in new Scope {
-      val result = state.set(1)
+      val result: Future[Int] = state.set(1)
       result.value shouldEqual Some(Success(0))
       state.value() shouldEqual 1
     }
@@ -58,7 +59,7 @@ class StateVarSpec extends AnyWordSpec with Matchers {
   }
 
   private trait Scope {
-    val serially = Serially.now
+    val serially: Serially = Serially.now
     val state = StateVar(0, serially)
   }
 }
diff --git a/version.sbt b/version.sbt
deleted file mode 100644
index 2094d25..0000000
--- a/version.sbt
+++ /dev/null
@@ -1 +0,0 @@
-ThisBuild / version := "1.0.6-SNAPSHOT"