diff --git a/.github/workflows/core-ci.yml b/.github/workflows/core-ci.yml
index 3ef8368..a080076 100644
--- a/.github/workflows/core-ci.yml
+++ b/.github/workflows/core-ci.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        spark: ["3.0.1", "3.1.3", "3.2.4", "3.3.4"]
+        spark: ["3.0.3", "3.1.3", "3.2.4", "3.3.4", "3.4.3", "3.5.3"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
diff --git a/build.sbt b/build.sbt
index 2bf0b03..0aed496 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,3 +1,5 @@
+import scala.language.postfixOps
+
 Compile / scalafmtOnCompile := true
 
 organization := "com.github.mrpowers"
@@ -5,12 +7,9 @@ name := "spark-daria"
 
 version := "1.2.3"
 
-crossScalaVersions := Seq("2.12.15", "2.13.8")
-scalaVersion := "2.12.15"
-
 val versionRegex = """^(.*)\.(.*)\.(.*)$""".r
 
-val scala2_13 = "2.13.14"
+val scala2_13 = "2.13.15"
 val scala2_12 = "2.12.20"
 
 val sparkVersion = System.getProperty("spark.testVersion", "3.3.4")
@@ -18,6 +17,7 @@ crossScalaVersions := {
   sparkVersion match {
     case versionRegex("3", m, _) if m.toInt >= 2 => Seq(scala2_12, scala2_13)
     case versionRegex("3", _, _) => Seq(scala2_12)
+    case versionRegex("4", _, _) => Seq(scala2_13)
   }
 }
 
@@ -32,9 +32,9 @@ lazy val commonSettings = Seq(
   libraryDependencies ++= Seq(
     "org.apache.spark"    %% "spark-sql"        % sparkVersion % "provided",
     "org.apache.spark"    %% "spark-mllib"      % sparkVersion % "provided",
-    "com.github.mrpowers" %% "spark-fast-tests" % "1.1.0"      % "test",
-    "com.lihaoyi"         %% "utest"            % "0.7.11"     % "test",
-    "com.lihaoyi"         %% "os-lib"           % "0.8.0"      % "test"
+    "com.github.mrpowers" %% "spark-fast-tests" % "1.3.0"      % "test",
+    "com.lihaoyi"         %% "utest"            % "0.8.2"      % "test",
+    "com.lihaoyi"         %% "os-lib"           % "0.10.3"     % "test"
   ),
 )
 
@@ -48,6 +48,18 @@ lazy val unsafe = (project in file("unsafe"))
   .settings(
     commonSettings,
     name := "unsafe",
+    Compile / unmanagedSourceDirectories ++= {
+      sparkVersion match {
+        case versionRegex(mayor, minor, _) =>
+          (Compile / sourceDirectory).value ** s"*spark_*$mayor.$minor*" / "scala" get
+      }
+    },
+    Test / unmanagedSourceDirectories ++= {
+      sparkVersion match {
+        case versionRegex(mayor, minor, _) =>
+          (Compile / sourceDirectory).value ** s"*spark_*$mayor.$minor*" / "scala" get
+      }
+    },
   )
 
 testFrameworks += new TestFramework("com.github.mrpowers.spark.daria.CustomFramework")