diff --git a/build.sbt b/build.sbt
index 61b8384a..f0008993 100644
--- a/build.sbt
+++ b/build.sbt
@@ -22,7 +22,7 @@ lazy val root = tlCrossRootProject.aggregate(servlet, examples)
 
 val asyncHttpClientVersion = "2.12.3"
 val jettyVersion = "10.0.13"
-val http4sVersion = "0.23.16"
+val http4sVersion = "0.23.17"
 val munitCatsEffectVersion = "1.0.7"
 val servletApiVersion = "4.0.1"
 
diff --git a/examples/src/main/scala/com/example/Bootstrap.scala b/examples/src/main/scala/com/example/Bootstrap.scala
index 93b0da4a..09983ffb 100644
--- a/examples/src/main/scala/com/example/Bootstrap.scala
+++ b/examples/src/main/scala/com/example/Bootstrap.scala
@@ -40,7 +40,9 @@ class Bootstrap extends ServletContextListener {
   @volatile private var shutdown: IO[Unit] = IO.unit
 
   override def contextInitialized(sce: ServletContextEvent): Unit = {
-    Dispatcher[IO].allocated
+    Dispatcher
+      .parallel[IO]
+      .allocated
       .flatMap { case (dispatcher, shutdown) =>
         IO(this.shutdown = shutdown) *>
           IO(sce.getServletContext.mountRoutes("example", routes, dispatcher = dispatcher))
diff --git a/servlet/src/main/scala/org/http4s/servlet/AsyncHttp4sServlet.scala b/servlet/src/main/scala/org/http4s/servlet/AsyncHttp4sServlet.scala
index 718aed26..32cd3a97 100644
--- a/servlet/src/main/scala/org/http4s/servlet/AsyncHttp4sServlet.scala
+++ b/servlet/src/main/scala/org/http4s/servlet/AsyncHttp4sServlet.scala
@@ -29,7 +29,7 @@ import javax.servlet.http.HttpServletResponse
 import scala.annotation.nowarn
 import scala.concurrent.duration.Duration
 
-class AsyncHttp4sServlet[F[_]] @deprecated("Use AsyncHttp4sServlet.builder", "0.23.16") (
+class AsyncHttp4sServlet[F[_]] @deprecated("Use AsyncHttp4sServlet.builder", "0.23.17") (
     httpApp: HttpApp[F],
     asyncTimeout: Duration = Duration.Inf,
     servletIo: ServletIo[F],
diff --git a/servlet/src/test/scala/org/http4s/servlet/AsyncHttp4sServletSuite.scala b/servlet/src/test/scala/org/http4s/servlet/AsyncHttp4sServletSuite.scala
index b3ff6b66..fbac1b63 100644
--- a/servlet/src/test/scala/org/http4s/servlet/AsyncHttp4sServletSuite.scala
+++ b/servlet/src/test/scala/org/http4s/servlet/AsyncHttp4sServletSuite.scala
@@ -57,7 +57,7 @@ class AsyncHttp4sServletSuite extends CatsEffectSuite {
     .orNotFound
 
   private val servletServer =
-    ResourceFixture[Int](Dispatcher[IO].flatMap(d => TestEclipseServer(servlet(d))))
+    ResourceFixture[Int](Dispatcher.parallel[IO].flatMap(d => TestEclipseServer(servlet(d))))
 
   private def get(client: HttpClient, serverPort: Int, path: String): IO[String] =
     IO.blocking(
@@ -134,7 +134,8 @@ class AsyncHttp4sServletSuite extends CatsEffectSuite {
   servletServer.test("AsyncHttp4sServlet handle two-chunk, deferred POST") { server =>
     // Show that we can read, be blocked, and read again
     val bytes = Stream.range(0, DefaultChunkSize).map(_.toByte).to(Array)
-    Dispatcher[IO]
+    Dispatcher
+      .parallel[IO]
       .use { dispatcher =>
         clientR.use { client =>
           for {
@@ -174,7 +175,8 @@ class AsyncHttp4sServletSuite extends CatsEffectSuite {
 
   // We shouldn't block when we receive less than a chunk at a time
   servletServer.test("AsyncHttp4sServlet handle two itsy-bitsy deferred chunk POST") { server =>
-    Dispatcher[IO]
+    Dispatcher
+      .parallel[IO]
       .use { dispatcher =>
         clientR.use { client =>
           for {
@@ -214,7 +216,8 @@ class AsyncHttp4sServletSuite extends CatsEffectSuite {
 
   servletServer.test("AsyncHttp4sServlet should not reorder lots of itsy-bitsy chunks") { server =>
     val body = (0 until 4096).map(_.toByte).toArray
-    Dispatcher[IO]
+    Dispatcher
+      .parallel[IO]
       .use { dispatcher =>
         clientR.use { client =>
           for {
diff --git a/servlet/src/test/scala/org/http4s/servlet/BlockingHttp4sServletSuite.scala b/servlet/src/test/scala/org/http4s/servlet/BlockingHttp4sServletSuite.scala
index e8491e8d..79070f11 100644
--- a/servlet/src/test/scala/org/http4s/servlet/BlockingHttp4sServletSuite.scala
+++ b/servlet/src/test/scala/org/http4s/servlet/BlockingHttp4sServletSuite.scala
@@ -48,7 +48,7 @@ class BlockingHttp4sServletSuite extends CatsEffectSuite {
     .orNotFound
 
   private val servletServer = ResourceFixture(
-    Dispatcher[IO].flatMap(d => TestEclipseServer(servlet(d)))
+    Dispatcher.parallel[IO].flatMap(d => TestEclipseServer(servlet(d)))
   )
 
   private def get(serverPort: Int, path: String): IO[String] =
diff --git a/servlet/src/test/scala/org/http4s/servlet/RouterInServletSuite.scala b/servlet/src/test/scala/org/http4s/servlet/RouterInServletSuite.scala
index 394334a3..2e87cc97 100644
--- a/servlet/src/test/scala/org/http4s/servlet/RouterInServletSuite.scala
+++ b/servlet/src/test/scala/org/http4s/servlet/RouterInServletSuite.scala
@@ -45,22 +45,28 @@ class RouterInServletSuite extends CatsEffectSuite {
   )
 
   private val serverWithoutRouter =
-    ResourceFixture[Int](Dispatcher[IO].flatMap(d => mkServer(mainRoutes, dispatcher = d)))
+    ResourceFixture[Int](Dispatcher.parallel[IO].flatMap(d => mkServer(mainRoutes, dispatcher = d)))
   private val server =
-    ResourceFixture[Int](Dispatcher[IO].flatMap(d => mkServer(router, dispatcher = d)))
+    ResourceFixture[Int](Dispatcher.parallel[IO].flatMap(d => mkServer(router, dispatcher = d)))
   private val serverWithContextPath =
     ResourceFixture[Int](
-      Dispatcher[IO].flatMap(d => mkServer(router, contextPath = "/context", dispatcher = d))
+      Dispatcher
+        .parallel[IO]
+        .flatMap(d => mkServer(router, contextPath = "/context", dispatcher = d))
     )
   private val serverWithServletPath =
     ResourceFixture[Int](
-      Dispatcher[IO].flatMap(d => mkServer(router, servletPath = "/servlet/*", dispatcher = d))
+      Dispatcher
+        .parallel[IO]
+        .flatMap(d => mkServer(router, servletPath = "/servlet/*", dispatcher = d))
     )
   private val serverWithContextAndServletPath =
     ResourceFixture[Int](
-      Dispatcher[IO].flatMap(d =>
-        mkServer(router, contextPath = "/context", servletPath = "/servlet/*", dispatcher = d)
-      )
+      Dispatcher
+        .parallel[IO]
+        .flatMap(d =>
+          mkServer(router, contextPath = "/context", servletPath = "/servlet/*", dispatcher = d)
+        )
     )
 
   serverWithoutRouter.test(