diff --git a/.scalafmt.conf b/.scalafmt.conf
index 06bf21490..6cea8df82 100644
--- a/.scalafmt.conf
+++ b/.scalafmt.conf
@@ -1,5 +1,5 @@
 version = 3.8.3
-runner.dialect = scala213
+runner.dialect = scala213source3
 assumeStandardLibraryStripMargin = true
 align.openParenCallSite = false
 align.openParenDefnSite = false
diff --git a/build.sbt b/build.sbt
index 5aefd8898..b053eda9b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -311,6 +311,14 @@ lazy val commonSettings = Def.settings(
 
 lazy val compileSettings = Def.settings(
   scalaVersion := Scala213,
+  scalacOptions ++= {
+    scalaBinaryVersion.value match {
+      case "2.13" =>
+        Seq("-Xsource:3-cross")
+      case _ =>
+        Nil
+    }
+  },
   doctestTestFramework := DoctestTestFramework.Munit
 )
 
diff --git a/modules/core/src/main/scala/org/scalasteward/core/buildtool/sbt/parser.scala b/modules/core/src/main/scala/org/scalasteward/core/buildtool/sbt/parser.scala
index 691aa5bf1..07ca6b0cd 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/buildtool/sbt/parser.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/buildtool/sbt/parser.scala
@@ -32,7 +32,7 @@ object parser {
     val chunks = fs2.Stream.emits(lines).map(removeSbtNoise).split(_ === "--- snip ---")
     val decoder = Decoder[Dependency].either(Decoder[Resolver])
     chunks.mapFilter { chunk =>
-      val (dependencies, resolvers) = chunk.toList.flatMap(decode(_)(decoder).toList).separate
+      val (dependencies, resolvers) = chunk.toList.flatMap(decode(_)(using decoder).toList).separate
       Option.when(dependencies.nonEmpty && resolvers.nonEmpty)(
         Scope(dependencies, resolvers.sorted)
       )
diff --git a/modules/core/src/main/scala/org/scalasteward/core/data/Version.scala b/modules/core/src/main/scala/org/scalasteward/core/data/Version.scala
index 0731484bf..db00d9c6e 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/data/Version.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/data/Version.scala
@@ -112,7 +112,7 @@ final case class Version(value: String) {
       case _                         => false
     } || Rfc5234.hexdig.rep(8).string.filterNot(startsWithDate).parse(value).isRight
 
-  private[this] def alnumComponentsWithoutPreRelease: List[Version.Component] =
+  private def alnumComponentsWithoutPreRelease: List[Version.Component] =
     alnumComponents.takeWhile {
       case a: Version.Component.Alpha => !a.isPreReleaseIdent
       case _                          => true
diff --git a/modules/core/src/main/scala/org/scalasteward/core/forge/github/GitHubAppApiAlg.scala b/modules/core/src/main/scala/org/scalasteward/core/forge/github/GitHubAppApiAlg.scala
index 94d3dc149..b04b4a332 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/forge/github/GitHubAppApiAlg.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/forge/github/GitHubAppApiAlg.scala
@@ -29,10 +29,10 @@ class GitHubAppApiAlg[F[_]](
     F: Concurrent[F]
 ) {
 
-  private[this] val acceptHeader =
+  private val acceptHeader =
     Header.Raw(ci"Accept", "application/vnd.github.v3+json")
 
-  private[this] def addHeaders(jwt: String): client.ModReq =
+  private def addHeaders(jwt: String): client.ModReq =
     req =>
       F.point(
         req.putHeaders(
diff --git a/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala b/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
index 40297a326..535d99d0c 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
@@ -71,7 +71,7 @@ final class FileGitAlg[F[_]](config: Config)(implicit
   ): F[Commit] = {
     val messages = message.paragraphs.foldMap(m => List("-m", m))
     val trailers = message.trailers.foldMap { case (k, v) => List("--trailer", s"$k=$v") }
-    git_("commit" :: "--all" :: sign :: signoff(signoffCommits) :: messages ++ trailers: _*)(
+    git_(("commit" :: "--all" :: sign :: signoff(signoffCommits) :: messages ++ trailers)*)(
       repo
     ) >>
       latestSha1(repo, Branch.head).map(Commit.apply)
@@ -181,7 +181,7 @@ final class FileGitAlg[F[_]](config: Config)(implicit
   }
 
   private def git_(args: String*)(repo: File): F[List[String]] =
-    git(args: _*)(repo, SlurpOptions.ignoreBufferOverflow)
+    git(args*)(repo, SlurpOptions.ignoreBufferOverflow)
 
   private val sign: String =
     if (config.gitCfg.signCommits) "--gpg-sign" else "--no-gpg-sign"
diff --git a/modules/core/src/main/scala/org/scalasteward/core/io/process.scala b/modules/core/src/main/scala/org/scalasteward/core/io/process.scala
index 3eb2c5ac8..79ce86ba2 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/io/process.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/io/process.scala
@@ -61,7 +61,7 @@ object process {
   )(implicit F: Async[F]): F[List[String]] =
     createProcess(args).flatMap { process =>
       F.delay(new ListBuffer[String]).flatMap { buffer =>
-        val raiseError = F.raiseError[List[String]] _
+        val raiseError = F.raiseError[List[String]]
 
         val result =
           readLinesIntoBuffer(process.getInputStream, buffer, maxBufferSize, log)
@@ -91,7 +91,7 @@ object process {
 
   private def createProcessBuilder[F[_]](args: Args)(implicit F: Sync[F]): F[ProcessBuilder] =
     F.blocking {
-      val pb = new ProcessBuilder(args.command.toList: _*)
+      val pb = new ProcessBuilder(args.command.toList*)
       args.workingDirectory.foreach(file => pb.directory(file.toJava))
       val env = pb.environment()
       if (args.slurpOptions(SlurpOption.ClearEnvironment)) env.clear()