diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b60b2de8..5a576251 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,6 +14,9 @@ jobs:
           - java: 8
             os: ubuntu-latest
             name: test_all
+          - java: 8
+            os: ubuntu-latest
+            name: scala_3
           - java: 8
             os: windows-latest
             name: scala_2_13 # TODO enable scripted test
@@ -49,6 +52,9 @@ jobs:
           "scala_2_13")
             sbt -v SetScala213 app/test lib/test
             ;;
+          "scala_3")
+            sbt -v '++ 3.x' app/test lib/test
+            ;;
           *)
             echo "unknown job"
             exit 1
diff --git a/build.sbt b/build.sbt
index 46f0be12..60b32617 100644
--- a/build.sbt
+++ b/build.sbt
@@ -67,7 +67,7 @@ lazy val app = (project in file("app"))
   .settings(
     description := "Command line tool to apply templates defined on GitHub",
     name := "giter8",
-    crossScalaVersions := List(scala212, scala213),
+    crossScalaVersions := List(scala212, scala213, scala3),
     csRun / sourceDirectory := {
       (baseDirectory).value.getParentFile / "src" / "main" / "conscript"
     },
@@ -144,7 +144,7 @@ lazy val gitsupport = (project in file("cli-git"))
   .settings(
     description := "cli and git support library for Giter8",
     name := "giter8-cli-git",
-    crossScalaVersions := List(scala212, scala213),
+    crossScalaVersions := List(scala212, scala213, scala3),
     libraryDependencies ++= Seq(
       scopt,
       jgit,
@@ -165,7 +165,7 @@ lazy val lib = (project in file("library"))
   .settings(
     name := "giter8-lib",
     description := "shared library for app and plugin",
-    crossScalaVersions := List(scala212, scala213),
+    crossScalaVersions := List(scala212, scala213, scala3),
     libraryDependencies ++= scalatest,
     libraryDependencies ++= Seq(
       stringTemplate,
@@ -189,7 +189,7 @@ lazy val launcher = (project in file("launcher"))
   .settings(
     description := "Command line tool to apply templates defined on GitHub",
     name := "giter8-launcher",
-    crossScalaVersions := List(scala212, scala213),
+    crossScalaVersions := List(scala212, scala213, scala3),
     libraryDependencies ++= Seq(
       coursier,
       verify % Test,
diff --git a/library/src/main/scala/g8.scala b/library/src/main/scala/g8.scala
index 6daf1b30..763b7115 100644
--- a/library/src/main/scala/g8.scala
+++ b/library/src/main/scala/g8.scala
@@ -482,7 +482,7 @@ object G8 {
       .toMap
   }
 
-  final case object NullInputException extends Throwable
+  case object NullInputException extends Throwable
 
   private def relativize(in: File, from: File): String = from.toURI().relativize(in.toURI).getPath
 
@@ -563,8 +563,8 @@ object G8 {
 
   def readProps(stm: InputStream): G8.OrderedProperties = {
     // Overrides java.util.Properties to return properties back in the order they were specified
+    val parameters = mutable.ListBuffer.empty[(String, String)]
     val properties = new Properties {
-      val parameters = mutable.ListBuffer.empty[(String, String)]
 
       override def put(key: Object, value: Object) = {
         val k = key.toString
@@ -577,7 +577,7 @@ object G8 {
 
     try {
       properties.load(stm)
-      properties.parameters.toList
+      parameters.toList
     } finally {
       stm.close()
     }
diff --git a/library/src/main/scala/maven.scala b/library/src/main/scala/maven.scala
index 73d8eb1c..b7137495 100644
--- a/library/src/main/scala/maven.scala
+++ b/library/src/main/scala/maven.scala
@@ -26,7 +26,7 @@ object Maven extends JavaTokenParsers with MavenHelper {
   private val org, name, release = """[\w\-\.]+""".r
 
   private val spec =
-    "maven" ~> "(" ~> org ~ ("," ~> name) ~ (("," ~> release) ?) <~ ")" ^^ { case org ~ name ~ release =>
+    "maven" ~> "(" ~> org ~ ("," ~> name) ~ (("," ~> release).?) <~ ")" ^^ { case org ~ name ~ release =>
       (org, name, release)
     }
 
diff --git a/library/src/test/scala/giter8/VersionNumberOrderingTest.scala b/library/src/test/scala/giter8/VersionNumberOrderingTest.scala
index b7fba982..72e8bdad 100644
--- a/library/src/test/scala/giter8/VersionNumberOrderingTest.scala
+++ b/library/src/test/scala/giter8/VersionNumberOrderingTest.scala
@@ -32,7 +32,7 @@ final class VersionNumberOrderingTest extends Properties("StableVersion") {
   private def genVersionNumber: Gen[VersionNumber] =
     for {
       n       <- Gen.choose(3, 4)
-      numbers <- Gen.listOfN(n, Gen.choose(0, 1000L))
+      numbers <- Gen.listOfN(n, Gen.choose(0L, 1000L))
       t       <- Gen.choose(1, 3)
       o       <- Gen.choose(1, 3)
       tags    <- Gen.listOfN(t, defaultGenStr)
@@ -47,32 +47,32 @@ final class VersionNumberOrderingTest extends Properties("StableVersion") {
 
   private def genSameMajorVersionNumbers: Gen[Seq[VersionNumber]] =
     for {
-      major          <- Gen.choose(0, 1000L)
+      major          <- Gen.choose(0L, 1000L)
       variations     <- Gen.choose(1, 5)
       versionNumbers <- fixedPrefixVersionNumbers(major)
     } yield versionNumbers
 
   private def genSameMajorAndMinorVersionNumbers: Gen[Seq[VersionNumber]] =
     for {
-      major          <- Gen.choose(0, 1000L)
-      minor          <- Gen.choose(0, 1000L)
+      major          <- Gen.choose(0L, 1000L)
+      minor          <- Gen.choose(0L, 1000L)
       versionNumbers <- fixedPrefixVersionNumbers(major, minor)
     } yield versionNumbers
 
   private def genSameMajorAndMinorAndPatchVersionNumbers: Gen[Seq[VersionNumber]] =
     for {
-      major          <- Gen.choose(0, 1000L)
-      minor          <- Gen.choose(0, 1000L)
-      patch          <- Gen.choose(0, 1000L)
+      major          <- Gen.choose(0L, 1000L)
+      minor          <- Gen.choose(0L, 1000L)
+      patch          <- Gen.choose(0L, 1000L)
       versionNumbers <- fixedPrefixVersionNumbers(major, minor, patch)
     } yield versionNumbers
 
   private def genSameMajorAndMinorAndPatchAndOtherVersionNumbers: Gen[Seq[VersionNumber]] =
     for {
-      major          <- Gen.choose(0, 1000L)
-      minor          <- Gen.choose(0, 1000L)
-      patch          <- Gen.choose(0, 1000L)
-      other          <- Gen.choose(0, 1000L)
+      major          <- Gen.choose(0L, 1000L)
+      minor          <- Gen.choose(0L, 1000L)
+      patch          <- Gen.choose(0L, 1000L)
+      other          <- Gen.choose(0L, 1000L)
       versionNumbers <- fixedPrefixVersionNumbers(major, minor, patch, other)
     } yield versionNumbers
 
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 81740925..a6c57ccf 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -30,6 +30,7 @@ object Dependencies {
   val sbtIo     = "org.scala-sbt" %% "io" % "1.10.0"
   val scala212  = "2.12.20"
   val scala213  = "2.13.15"
+  val scala3    = "3.3.4"
   val sbt1      = "1.2.8"
   val scalaXml  = "org.scala-lang.modules" %% "scala-xml" % "2.1.0"
   def parserCombinator(scalaVersion: String) = "org.scala-lang.modules" %% "scala-parser-combinators" % {