diff --git a/project/ProjectPlugin.scala b/project/ProjectPlugin.scala
index 98603ce6..f41111b5 100644
--- a/project/ProjectPlugin.scala
+++ b/project/ProjectPlugin.scala
@@ -16,7 +16,7 @@ object ProjectPlugin extends AutoPlugin {
 
     object V {
       lazy val cats                = "2.9.0"
-      lazy val catsEffect          = "2.5.5"
+      lazy val catsEffect          = "3.4.7"
       lazy val http4s              = "0.21.34"
       lazy val circe               = "0.14.2"
       lazy val log4s               = "1.7.0"
diff --git a/server/src/main/scala/org/scalaexercises/evaluator/evaluation.scala b/server/src/main/scala/org/scalaexercises/evaluator/evaluation.scala
index 88d5adee..4a9b5646 100644
--- a/server/src/main/scala/org/scalaexercises/evaluator/evaluation.scala
+++ b/server/src/main/scala/org/scalaexercises/evaluator/evaluation.scala
@@ -39,10 +39,11 @@ import scala.tools.nsc.reporters._
 import scala.tools.nsc.{Global, Settings}
 import scala.util.{Failure, Success, Try}
 import scala.util.control.NonFatal
+import cats.effect.Temporal
 
 class Evaluator[F[_]: Sync](timeout: FiniteDuration = 20.seconds)(implicit
     F: ConcurrentEffect[F],
-    T: Timer[F]
+    T: Temporal[F]
 ) {
   type Remote = String
 
diff --git a/server/src/main/scala/org/scalaexercises/evaluator/services.scala b/server/src/main/scala/org/scalaexercises/evaluator/services.scala
index 8a67c58b..f86b6d25 100644
--- a/server/src/main/scala/org/scalaexercises/evaluator/services.scala
+++ b/server/src/main/scala/org/scalaexercises/evaluator/services.scala
@@ -16,7 +16,7 @@
 
 package org.scalaexercises.evaluator
 
-import cats.effect.{ConcurrentEffect, ContextShift, ExitCode, IO, IOApp, Timer}
+import cats.effect.{ConcurrentEffect, ExitCode, IO, IOApp}
 import cats.implicits._
 import coursier.interop.cats._
 import coursier.util.Sync