diff --git a/build.sbt b/build.sbt
index 7be60c6..da59658 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,15 +1,15 @@
-lazy val catsEffectVersion    = "1.1.0"
-lazy val catsVersion          = "1.5.0"
-lazy val circeVersion         = "0.10.0"
-lazy val doobieVersion        = "0.6.0"
-lazy val fs2Version           = "1.0.2"
-lazy val kindProjectorVersion = "0.9.9"
-lazy val log4catsVersion      = "0.2.0"
-lazy val sangriaCirceVersion  = "1.2.1"
+lazy val catsEffectVersion    = "2.1.3"
+lazy val catsVersion          = "2.1.1"
+lazy val circeVersion         = "0.13.0"
+lazy val doobieVersion        = "0.9.0"
+lazy val fs2Version           = "2.3.0"
+lazy val kindProjectorVersion = "0.9.10"
+lazy val log4catsVersion      = "1.0.1"
+lazy val sangriaCirceVersion  = "1.3.0"
 lazy val sangriaVersion       = "1.4.2"
-lazy val scala12Version       = "2.12.8"
-lazy val http4sVersion        = "0.20.0-M4"
-lazy val slf4jVersion         = "1.7.25"
+lazy val scala12Version       = "2.12.11"
+lazy val http4sVersion        = "0.21.4"
+lazy val slf4jVersion         = "1.7.30"
 
 lazy val scalacSettings = Seq(
   scalacOptions ++=
diff --git a/modules/core/src/main/scala/Main.scala b/modules/core/src/main/scala/Main.scala
index 515e8e8..f5ead05 100644
--- a/modules/core/src/main/scala/Main.scala
+++ b/modules/core/src/main/scala/Main.scala
@@ -23,12 +23,13 @@ import org.http4s.implicits._
 import org.http4s.server.Server
 import org.http4s.server.blaze._
 import scala.concurrent.ExecutionContext
+import scala.concurrent.ExecutionContext.global
 
 object Main extends IOApp {
 
   // Construct a transactor for connecting to the database.
   def transactor[F[_]: Async: ContextShift](
-    bec: ExecutionContext
+    blocker: Blocker
   ): Resource[F, HikariTransactor[F]] =
     ExecutionContexts.fixedThreadPool[F](10).flatMap { ce =>
       HikariTransactor.newHikariTransactor(
@@ -37,7 +38,7 @@ object Main extends IOApp {
         "user",
         "password",
         ce,
-        bec
+        blocker
       )
     }
 
@@ -58,14 +59,14 @@ object Main extends IOApp {
 
   // Playground or else redirect to playground
   def playgroundOrElse[F[_]: Sync: ContextShift](
-    blockingContext: ExecutionContext
+    blocker: Blocker
   ): HttpRoutes[F] = {
     object dsl extends Http4sDsl[F]; import dsl._
     HttpRoutes.of[F] {
 
       case GET -> Root / "playground.html" =>
         StaticFile
-          .fromResource[F]("/assets/playground.html", blockingContext)
+          .fromResource[F]("/assets/playground.html", blocker)
           .getOrElseF(NotFound())
 
       case _ =>
@@ -78,7 +79,7 @@ object Main extends IOApp {
   def server[F[_]: ConcurrentEffect: ContextShift: Timer](
     routes: HttpRoutes[F]
   ): Resource[F, Server[F]] =
-    BlazeServerBuilder[F]
+    BlazeServerBuilder[F](global)
       .bindHttp(8080, "localhost")
       .withHttpApp(routes.orNotFound)
       .resource
@@ -88,16 +89,16 @@ object Main extends IOApp {
     implicit L: Logger[F]
   ): Resource[F, Server[F]] =
     for {
-      bec <- ExecutionContexts.cachedThreadPool[F]
-      xa  <- transactor[F](bec)
-      gql  = graphQL[F](xa, bec)
-      rts  = GraphQLRoutes[F](gql) <+> playgroundOrElse(bec)
+      b   <- Blocker[F]
+      xa  <- transactor[F](b)
+      gql  = graphQL[F](xa, b.blockingContext)
+      rts  = GraphQLRoutes[F](gql) <+> playgroundOrElse(b)
       svr <- server[F](rts)
     } yield svr
 
   // Our entry point starts the server and blocks forever.
   def run(args: List[String]): IO[ExitCode] = {
-    implicit val log = Slf4jLogger.unsafeCreate[IO]
+    implicit val log = Slf4jLogger.getLogger[IO]
     resource[IO].use(_ => IO.never.as(ExitCode.Success))
   }
 
diff --git a/modules/core/src/main/scala/repo/CityRepo.scala b/modules/core/src/main/scala/repo/CityRepo.scala
index 5be8583..93a2cd6 100644
--- a/modules/core/src/main/scala/repo/CityRepo.scala
+++ b/modules/core/src/main/scala/repo/CityRepo.scala
@@ -4,7 +4,7 @@
 
 package demo.repo
 
-import cats._
+import cats.effect._
 import cats.implicits._
 import doobie._
 import doobie.implicits._
@@ -18,7 +18,7 @@ trait CityRepo[F[_]] {
 
 object CityRepo {
 
-  def fromTransactor[F[_]: Monad: Logger](xa: Transactor[F]): CityRepo[F] =
+  def fromTransactor[F[_]: Sync: Logger](xa: Transactor[F]): CityRepo[F] =
     new CityRepo[F] {
 
       val select: Fragment =
@@ -37,4 +37,4 @@ object CityRepo {
 
     }
 
-}
\ No newline at end of file
+}
diff --git a/modules/core/src/main/scala/repo/CountryRepo.scala b/modules/core/src/main/scala/repo/CountryRepo.scala
index 80a7f75..e2045eb 100644
--- a/modules/core/src/main/scala/repo/CountryRepo.scala
+++ b/modules/core/src/main/scala/repo/CountryRepo.scala
@@ -4,8 +4,8 @@
 
 package demo.repo
 
-import cats._
 import cats.data._
+import cats.effect._
 import cats.implicits._
 import doobie._
 import doobie.implicits._
@@ -21,7 +21,7 @@ trait CountryRepo[F[_]] {
 
 object CountryRepo {
 
-  def fromTransactor[F[_]: Monad: Logger](xa: Transactor[F]): CountryRepo[F] =
+  def fromTransactor[F[_]: Sync: Logger](xa: Transactor[F]): CountryRepo[F] =
     new CountryRepo[F] {
 
       val select: Fragment =
@@ -56,4 +56,4 @@ object CountryRepo {
 
     }
 
-}
\ No newline at end of file
+}
diff --git a/modules/core/src/main/scala/repo/LanguageRepo.scala b/modules/core/src/main/scala/repo/LanguageRepo.scala
index 6841326..a04e69c 100644
--- a/modules/core/src/main/scala/repo/LanguageRepo.scala
+++ b/modules/core/src/main/scala/repo/LanguageRepo.scala
@@ -4,8 +4,8 @@
 
 package demo.repo
 
-import cats._
 import cats.data._
+import cats.effect.Sync
 import cats.implicits._
 import doobie._
 import doobie.implicits._
@@ -19,7 +19,7 @@ trait LanguageRepo[F[_]] {
 
 object LanguageRepo {
 
-  def fromTransactor[F[_]: Monad: Logger](xa: Transactor[F]): LanguageRepo[F] =
+  def fromTransactor[F[_]: Sync: Logger](xa: Transactor[F]): LanguageRepo[F] =
     new LanguageRepo[F] {
 
       val select: Fragment =
@@ -51,4 +51,4 @@ object LanguageRepo {
 
     }
 
-}
\ No newline at end of file
+}
diff --git a/modules/core/src/main/scala/repo/MasterRepo.scala b/modules/core/src/main/scala/repo/MasterRepo.scala
index 882f310..b8f9a58 100644
--- a/modules/core/src/main/scala/repo/MasterRepo.scala
+++ b/modules/core/src/main/scala/repo/MasterRepo.scala
@@ -4,7 +4,7 @@
 
 package demo.repo
 
-import cats._
+import cats.effect._
 import doobie._
 import io.chrisdavenport.log4cats.Logger
 
@@ -16,11 +16,11 @@ final case class MasterRepo[F[_]](
 
 object MasterRepo {
 
-  def fromTransactor[F[_]: Monad: Logger](xa: Transactor[F]): MasterRepo[F] =
+  def fromTransactor[F[_]: Sync: Logger](xa: Transactor[F]): MasterRepo[F] =
     MasterRepo(
       CityRepo.fromTransactor(xa),
       CountryRepo.fromTransactor(xa),
       LanguageRepo.fromTransactor(xa)
     )
 
-}
\ No newline at end of file
+}
diff --git a/modules/core/src/main/scala/sangria/SangriaGraphQL.scala b/modules/core/src/main/scala/sangria/SangriaGraphQL.scala
index 8562555..af0fae5 100644
--- a/modules/core/src/main/scala/sangria/SangriaGraphQL.scala
+++ b/modules/core/src/main/scala/sangria/SangriaGraphQL.scala
@@ -13,7 +13,6 @@ import _root_.sangria.marshalling.circe._
 import _root_.sangria.parser.{ QueryParser, SyntaxError }
 import _root_.sangria.schema._
 import _root_.sangria.validation._
-import cats._
 import cats.effect._
 import cats.implicits._
 import io.circe.{ Json, JsonObject }
@@ -70,8 +69,7 @@ object SangriaGraphQL {
       userContext: F[A],
       blockingExecutionContext: ExecutionContext
     )(
-      implicit F: MonadError[F, Throwable],
-               L: LiftIO[F]
+      implicit F: Async[F],
     ): GraphQL[F] =
       new GraphQL[F] {
 
@@ -107,21 +105,22 @@ object SangriaGraphQL {
           variables:     JsonObject
         )(implicit ec: ExecutionContext): F[Either[Json, Json]] =
           userContext.flatMap { ctx =>
-            IO.fromFuture {
-              IO {
-                Executor.execute(
-                  schema           = schema,
-                  deferredResolver = deferredResolver,
-                  queryAst         = query,
-                  userContext      = ctx,
-                  variables        = Json.fromJsonObject(variables),
-                  operationName    = operationName,
-                  exceptionHandler = ExceptionHandler {
-                    case (_, e) ⇒ HandledException(e.getMessage)
-                  }
-                )
+            F.async { (cb: Either[Throwable, Json] => Unit) =>
+              Executor.execute(
+                schema           = schema,
+                deferredResolver = deferredResolver,
+                queryAst         = query,
+                userContext      = ctx,
+                variables        = Json.fromJsonObject(variables),
+                operationName    = operationName,
+                exceptionHandler = ExceptionHandler {
+                  case (_, e) ⇒ HandledException(e.getMessage)
+                }
+              ).onComplete {
+                case Success(value) => cb(Right(value))
+                case Failure(error) => cb(Left(error))
               }
-            } .to[F]
+            }
           } .attempt.flatMap {
             case Right(json)               => F.pure(json.asRight)
             case Left(err: WithViolations) => fail(formatWithViolations(err))
diff --git a/project/build.properties b/project/build.properties
index 0cd8b07..797e7cc 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.2.3
+sbt.version=1.3.10
diff --git a/project/plugins.sbt b/project/plugins.sbt
index f975e14..f30b599 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,4 +1,6 @@
-addSbtPlugin("com.timushev.sbt"   % "sbt-updates"     % "0.3.4")
-addSbtPlugin("de.heikoseeberger"  % "sbt-header"      % "5.0.0")
+scalaVersion := "2.12.11"
+
+addSbtPlugin("com.timushev.sbt"   % "sbt-updates"     % "0.5.0")
+addSbtPlugin("de.heikoseeberger"  % "sbt-header"      % "5.6.0")
 addSbtPlugin("io.spray"           % "sbt-revolver"    % "0.9.1")