diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 82279f83f3f..6c8d484d170 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,110 +29,42 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        scala: [3.0.2, 2.12.15, 2.13.8]
-        java: [temurin@8, temurin@11, temurin@17]
-        exclude:
-          - scala: 3.0.2
-            java: temurin@11
-          - scala: 3.0.2
-            java: temurin@17
-          - scala: 2.12.15
-            java: temurin@11
-          - scala: 2.12.15
-            java: temurin@17
+        scala: ["3.3.4", "2.12.18", "2.13.11"]
+        java:
+          - { java-version: "17", java-distribution: "temurin" }
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout current branch (full)
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Download Java (temurin@8)
-        id: download-java-temurin-8
-        if: matrix.java == 'temurin@8'
-        uses: typelevel/download-java@v1
+      - name: Setup Java (${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }})
+        uses: actions/setup-java@v4.4.0
         with:
-          distribution: temurin
-          java-version: 8
+          distribution: ${{ matrix.java.java-distribution }}
+          java-version: ${{ matrix.java.java-version }}
+          cache: 'sbt'
+      - uses: sbt/setup-sbt@v1
 
-      - name: Setup Java (temurin@8)
-        if: matrix.java == 'temurin@8'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 8
-          jdkFile: ${{ steps.download-java-temurin-8.outputs.jdkFile }}
-
-      - name: Download Java (temurin@11)
-        id: download-java-temurin-11
-        if: matrix.java == 'temurin@11'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 11
-
-      - name: Setup Java (temurin@11)
-        if: matrix.java == 'temurin@11'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 11
-          jdkFile: ${{ steps.download-java-temurin-11.outputs.jdkFile }}
-
-      - name: Download Java (temurin@17)
-        id: download-java-temurin-17
-        if: matrix.java == 'temurin@17'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 17
-
-      - name: Setup Java (temurin@17)
-        if: matrix.java == 'temurin@17'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 17
-          jdkFile: ${{ steps.download-java-temurin-17.outputs.jdkFile }}
-
-      - name: Cache sbt
-        uses: actions/cache@v2
-        with:
-          path: |
-            ~/.sbt
-            ~/.ivy2/cache
-            ~/.coursier/cache/v1
-            ~/.cache/coursier/v1
-            ~/AppData/Local/Coursier/Cache/v1
-            ~/Library/Caches/Coursier/v1
-          key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
-
-      - name: Check that workflows are up to date
-        run: sbt '++${{ matrix.scala }}' 'project /' githubWorkflowCheck
-
-      - name: Check headers and formatting
-        if: matrix.java == 'temurin@8'
-        run: sbt '++${{ matrix.scala }}' headerCheckAll scalafmtCheckAll 'project /' scalafmtSbtCheck
+#      - name: Check that workflows are up to date
+#        run: sbt '++${{ matrix.scala }}' 'project /' githubWorkflowCheck
 
       - name: Test
         run: sbt '++${{ matrix.scala }}' test
 
       - name: Check binary compatibility
-        if: matrix.java == 'temurin@8'
+        if: matrix.java == 'temurin@17'
         run: sbt '++${{ matrix.scala }}' mimaReportBinaryIssues
 
       - name: Generate API documentation
-        if: matrix.java == 'temurin@8'
+        if: matrix.java == 'temurin@17'
         run: sbt '++${{ matrix.scala }}' doc
 
       - name: Check Scalafix rules
-        if: matrix.scala != '3.0.2'
+        if: matrix.scala != '3.3.4'
         run: sbt '++${{ matrix.scala }}' 'scalafixAll --check'
 
-      - name: Check unused compile dependencies
-        if: matrix.java == 'temurin@8'
-        run: sbt '++${{ matrix.scala }}' unusedCompileDependenciesTest
-
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/series/0.22')
         run: mkdir -p examples/ember/target blaze-client/target server/target examples/target scalafix-internal/input/target blaze-server/target scalafix-internal/tests/target scalatags/target target examples/docker/target twirl/target unidocs/target site/target laws/target tests/target tomcat-server/target prometheus-metrics/target scalafix-internal/output/target servlet/target examples/tomcat/target examples/jetty/target testing/target ember-server/target okhttp-client/target examples/blaze/target scalafix-internal/rules/target client/target blaze-core/target circe/target examples/war/target jetty-client/target ember-client/target boopickle/target play-json/target async-http-client/target core/target scala-xml/target dsl/target dropwizard-metrics/target jetty-server/target ember-core/target jawn/target bench/target project/target
@@ -143,9 +75,9 @@ jobs:
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/series/0.22')
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-${{ matrix.scala }}
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-${{ matrix.scala }}
           path: targets.tar
 
   publish:
@@ -155,121 +87,70 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.13.8]
-        java: [temurin@8]
+        scala: [2.13.11]
+        java:
+          - { java-version: "17", java-distribution: "temurin" }
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout current branch (full)
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Download Java (temurin@8)
-        id: download-java-temurin-8
-        if: matrix.java == 'temurin@8'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 8
-
-      - name: Setup Java (temurin@8)
-        if: matrix.java == 'temurin@8'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 8
-          jdkFile: ${{ steps.download-java-temurin-8.outputs.jdkFile }}
-
-      - name: Download Java (temurin@11)
-        id: download-java-temurin-11
-        if: matrix.java == 'temurin@11'
-        uses: typelevel/download-java@v1
+      - name: Setup Java (${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }})
+        uses: actions/setup-java@v4.4.0
         with:
-          distribution: temurin
-          java-version: 11
+          distribution: ${{ matrix.java.java-distribution }}
+          java-version: ${{ matrix.java.java-version }}
+          cache: 'sbt'
+      - uses: sbt/setup-sbt@v1
 
-      - name: Setup Java (temurin@11)
-        if: matrix.java == 'temurin@11'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 11
-          jdkFile: ${{ steps.download-java-temurin-11.outputs.jdkFile }}
-
-      - name: Download Java (temurin@17)
-        id: download-java-temurin-17
-        if: matrix.java == 'temurin@17'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 17
-
-      - name: Setup Java (temurin@17)
-        if: matrix.java == 'temurin@17'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 17
-          jdkFile: ${{ steps.download-java-temurin-17.outputs.jdkFile }}
-
-      - name: Cache sbt
-        uses: actions/cache@v2
-        with:
-          path: |
-            ~/.sbt
-            ~/.ivy2/cache
-            ~/.coursier/cache/v1
-            ~/.cache/coursier/v1
-            ~/AppData/Local/Coursier/Cache/v1
-            ~/Library/Caches/Coursier/v1
-          key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
-
-      - name: Download target directories (3.0.2)
+      - name: Download target directories (3.3.4)
         uses: actions/download-artifact@v2
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-3.0.2
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-3.3.4
 
-      - name: Inflate target directories (3.0.2)
+      - name: Inflate target directories (3.3.4)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.12.15)
+      - name: Download target directories (2.12.18)
         uses: actions/download-artifact@v2
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12.15
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-2.12.18
 
-      - name: Inflate target directories (2.12.15)
+      - name: Inflate target directories (2.12.18)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13.8)
+      - name: Download target directories (2.13.11)
         uses: actions/download-artifact@v2
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13.8
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-2.13.11
 
-      - name: Inflate target directories (2.13.8)
+      - name: Inflate target directories (2.13.11)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13.8)
+      - name: Download target directories (2.13.11)
         uses: actions/download-artifact@v2
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13.8
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-2.13.11
 
-      - name: Inflate target directories (2.13.8)
+      - name: Inflate target directories (2.13.11)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13.8)
+      - name: Download target directories (2.13.11)
         uses: actions/download-artifact@v2
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13.8
+          name: target-${{ matrix.os }}-${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }}-2.13.11
 
-      - name: Inflate target directories (2.13.8)
+      - name: Inflate target directories (2.13.11)
         run: |
           tar xf targets.tar
           rm targets.tar
@@ -293,77 +174,26 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [3.0.2, 2.12.15, 2.13.8]
-        java: [temurin@8]
+        scala: ["3.3.4", "2.12.18", "2.13.11"]
+        java:
+          - { java-version: "17", java-distribution: "temurin" }
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout current branch (full)
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Download Java (temurin@8)
-        id: download-java-temurin-8
-        if: matrix.java == 'temurin@8'
-        uses: typelevel/download-java@v1
+      - name: Setup Java (${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }})
+        uses: actions/setup-java@v4.4.0
         with:
-          distribution: temurin
-          java-version: 8
-
-      - name: Setup Java (temurin@8)
-        if: matrix.java == 'temurin@8'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 8
-          jdkFile: ${{ steps.download-java-temurin-8.outputs.jdkFile }}
-
-      - name: Download Java (temurin@11)
-        id: download-java-temurin-11
-        if: matrix.java == 'temurin@11'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 11
-
-      - name: Setup Java (temurin@11)
-        if: matrix.java == 'temurin@11'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 11
-          jdkFile: ${{ steps.download-java-temurin-11.outputs.jdkFile }}
-
-      - name: Download Java (temurin@17)
-        id: download-java-temurin-17
-        if: matrix.java == 'temurin@17'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 17
-
-      - name: Setup Java (temurin@17)
-        if: matrix.java == 'temurin@17'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 17
-          jdkFile: ${{ steps.download-java-temurin-17.outputs.jdkFile }}
-
-      - name: Cache sbt
-        uses: actions/cache@v2
-        with:
-          path: |
-            ~/.sbt
-            ~/.ivy2/cache
-            ~/.coursier/cache/v1
-            ~/.cache/coursier/v1
-            ~/AppData/Local/Coursier/Cache/v1
-            ~/Library/Caches/Coursier/v1
-          key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
+          distribution: ${{ matrix.java.java-distribution }}
+          java-version: ${{ matrix.java.java-version }}
+          cache: 'sbt'
+      - uses: sbt/setup-sbt@v1
 
       - name: Scalafix tests
-        if: matrix.scala == '2.13.8'
+        if: matrix.scala == '2.13.11'
         run: |
           cd scalafix
           sbt ci
@@ -373,74 +203,23 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.13.8]
-        java: [temurin@8]
+        scala: [2.13.11]
+        java:
+          - { java-version: "17", java-distribution: "temurin" }
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout current branch (full)
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Download Java (temurin@8)
-        id: download-java-temurin-8
-        if: matrix.java == 'temurin@8'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 8
-
-      - name: Setup Java (temurin@8)
-        if: matrix.java == 'temurin@8'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 8
-          jdkFile: ${{ steps.download-java-temurin-8.outputs.jdkFile }}
-
-      - name: Download Java (temurin@11)
-        id: download-java-temurin-11
-        if: matrix.java == 'temurin@11'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 11
-
-      - name: Setup Java (temurin@11)
-        if: matrix.java == 'temurin@11'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 11
-          jdkFile: ${{ steps.download-java-temurin-11.outputs.jdkFile }}
-
-      - name: Download Java (temurin@17)
-        id: download-java-temurin-17
-        if: matrix.java == 'temurin@17'
-        uses: typelevel/download-java@v1
-        with:
-          distribution: temurin
-          java-version: 17
-
-      - name: Setup Java (temurin@17)
-        if: matrix.java == 'temurin@17'
-        uses: actions/setup-java@v2
-        with:
-          distribution: jdkfile
-          java-version: 17
-          jdkFile: ${{ steps.download-java-temurin-17.outputs.jdkFile }}
-
-      - name: Cache sbt
-        uses: actions/cache@v2
+      - name: Setup Java (${{ matrix.java.java-distribution }}@${{ matrix.java.java-version }})
+        uses: actions/setup-java@v4.4.0
         with:
-          path: |
-            ~/.sbt
-            ~/.ivy2/cache
-            ~/.coursier/cache/v1
-            ~/.cache/coursier/v1
-            ~/AppData/Local/Coursier/Cache/v1
-            ~/Library/Caches/Coursier/v1
-          key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
+          distribution: ${{ matrix.java.java-distribution }}
+          java-version: ${{ matrix.java.java-version }}
+          cache: 'sbt'
+      - uses: sbt/setup-sbt@v1
 
       - name: Generate site
         run: sbt '++${{ matrix.scala }}' site/tlSite
diff --git a/blaze-core/src/main/scala/org/http4s/blazecore/util/CachingChunkWriter.scala b/blaze-core/src/main/scala/org/http4s/blazecore/util/CachingChunkWriter.scala
index 94a3fdaa3b2..78ec0f9f386 100644
--- a/blaze-core/src/main/scala/org/http4s/blazecore/util/CachingChunkWriter.scala
+++ b/blaze-core/src/main/scala/org/http4s/blazecore/util/CachingChunkWriter.scala
@@ -25,6 +25,7 @@ import org.http4s.util.StringWriter
 
 import java.nio.ByteBuffer
 import java.nio.charset.StandardCharsets.ISO_8859_1
+import scala.annotation.nowarn
 import scala.collection.mutable.Buffer
 import scala.concurrent._
 
@@ -38,6 +39,7 @@ private[http4s] class CachingChunkWriter[F[_]](
   import ChunkWriter._
 
   private[this] var pendingHeaders: StringWriter = _
+  @nowarn("msg=local var .* is never updated")
   private[this] var bodyBuffer: Buffer[Chunk[Byte]] = Buffer()
   private[this] var size: Int = 0
 
diff --git a/build.sbt b/build.sbt
index 457fcb54d0c..737354c9045 100644
--- a/build.sbt
+++ b/build.sbt
@@ -231,6 +231,9 @@ lazy val server = libraryProject("server")
   .settings(
     description := "Base library for building http4s servers",
     startYear := Some(2014),
+    libraryDependencies ++= Seq(
+      scalacCompatAnnotation
+    ),
     mimaBinaryIssueFilters ++= Seq(
       ProblemFilters.exclude[IncompatibleMethTypeProblem](
         "org.http4s.server.middleware.CSRF.this"
@@ -581,6 +584,7 @@ lazy val jettyClient = libraryProject("jetty-client")
       Http4sPlugin.jettyClient,
       jettyHttp,
       jettyUtil,
+      scalaJava8Compat,
     ),
   )
   .dependsOn(core, testing % "test->test", client % "compile;test->test")
@@ -888,7 +892,7 @@ lazy val scalafixInternalRules = project
   .settings(
     startYear := Some(2021),
     libraryDependencies ++= Seq(
-      "ch.epfl.scala" %% "scalafix-core" % _root_.scalafix.sbt.BuildInfo.scalafixVersion
+      "ch.epfl.scala" %% "scalafix-core" % V.scalafix
     ).filter(_ => !tlIsScala3.value),
   )
 
@@ -931,6 +935,12 @@ lazy val scalafixInternalTests = project
   .settings(headerSources / excludeFilter := AllPassFilter)
   .disablePlugins(ScalafixPlugin)
   .dependsOn(scalafixInternalRules)
+  .settings(
+    dependencyOverrides ++= Seq(
+      "ch.epfl.scala" %% "scalafix-core" % V.scalafix,
+      "ch.epfl.scala" %% "scalafix-testkit" % V.scalafix % Test cross CrossVersion.full,
+    )
+  )
 
 def http4sProject(name: String) =
   Project(name, file(name))
diff --git a/jetty-client/src/main/scala/org/http4s/jetty/client/JettyClient.scala b/jetty-client/src/main/scala/org/http4s/jetty/client/JettyClient.scala
index fc8dfa11b1f..a90569cbe31 100644
--- a/jetty-client/src/main/scala/org/http4s/jetty/client/JettyClient.scala
+++ b/jetty-client/src/main/scala/org/http4s/jetty/client/JettyClient.scala
@@ -22,9 +22,8 @@ import cats.effect._
 import cats.syntax.all._
 import fs2._
 import org.eclipse.jetty.client.HttpClient
-import org.eclipse.jetty.client.api.{Request => JettyRequest}
+import org.eclipse.jetty.client.{Request => JettyRequest}
 import org.eclipse.jetty.http.{HttpVersion => JHttpVersion}
-import org.eclipse.jetty.util.ssl.SslContextFactory
 import org.http4s.client.Client
 import org.log4s.Logger
 import org.log4s.getLogger
@@ -34,7 +33,7 @@ object JettyClient {
 
   def allocate[F[_]](
       client: HttpClient = defaultHttpClient()
-  )(implicit F: ConcurrentEffect[F]): F[(Client[F], F[Unit])] = {
+  )(implicit F: ConcurrentEffect[F], CS: ContextShift[F]): F[(Client[F], F[Unit])] = {
     val acquire = F
       .pure(client)
       .flatTap(client => F.delay(client.start()))
@@ -46,7 +45,7 @@ object JettyClient {
                 jReq <- F.catchNonFatal(toJettyRequest(client, req, dcp))
                 rl <- ResponseListener(cb)
                 _ <- F.delay(jReq.send(rl))
-                _ <- dcp.write(req)
+                _ <- dcp.write(req.body)
               } yield ()).recover { case e =>
                 cb(Left(e))
               }
@@ -62,19 +61,18 @@ object JettyClient {
     acquire.map((_, dispose))
   }
 
-  def resource[F[_]](client: HttpClient = defaultHttpClient())(implicit
-      F: ConcurrentEffect[F]
+  def resource[F[_]: ConcurrentEffect: ContextShift](
+      client: HttpClient = defaultHttpClient()
   ): Resource[F, Client[F]] =
     Resource(allocate[F](client))
 
-  def stream[F[_]](client: HttpClient = defaultHttpClient())(implicit
-      F: ConcurrentEffect[F]
+  def stream[F[_]: ConcurrentEffect: ContextShift](
+      client: HttpClient = defaultHttpClient()
   ): Stream[F, Client[F]] =
     Stream.resource(resource(client))
 
   def defaultHttpClient(): HttpClient = {
-    val sslCtxFactory = new SslContextFactory.Client();
-    val c = new HttpClient(sslCtxFactory)
+    val c = new HttpClient()
     c.setFollowRedirects(false)
     c.setDefaultRequestContentType(null)
     c
@@ -96,9 +94,10 @@ object JettyClient {
           case _ => JHttpVersion.HTTP_1_1
         }
       )
-
-    for (h <- request.headers.headers if h.isNameValid)
-      jReq.header(h.name.toString, h.value)
-    jReq.content(dcp)
+    jReq.headers { jettyHeaders =>
+      for (h <- request.headers.headers if h.isNameValid)
+        jettyHeaders.add(h.name.toString, h.value)
+    }
+    jReq.body(dcp)
   }
 }
diff --git a/jetty-client/src/main/scala/org/http4s/jetty/client/ResponseListener.scala b/jetty-client/src/main/scala/org/http4s/jetty/client/ResponseListener.scala
index 82d8774aadc..86f52237c12 100644
--- a/jetty-client/src/main/scala/org/http4s/jetty/client/ResponseListener.scala
+++ b/jetty-client/src/main/scala/org/http4s/jetty/client/ResponseListener.scala
@@ -24,11 +24,10 @@ import cats.syntax.all._
 import fs2.Stream._
 import fs2._
 import fs2.concurrent.Queue
-import org.eclipse.jetty.client.api.Result
-import org.eclipse.jetty.client.api.{Response => JettyResponse}
+import org.eclipse.jetty.client.Result
+import org.eclipse.jetty.client.{Response => JettyResponse}
 import org.eclipse.jetty.http.HttpFields
 import org.eclipse.jetty.http.{HttpVersion => JHttpVersion}
-import org.eclipse.jetty.util.{Callback => JettyCallback}
 import org.http4s.internal.CollectionCompat.CollectionConverters._
 import org.http4s.internal.invokeCallback
 import org.http4s.internal.loggingAsyncCallback
@@ -40,8 +39,8 @@ import java.nio.ByteBuffer
 private[jetty] final case class ResponseListener[F[_]](
     queue: Queue[F, Item],
     cb: Callback[Resource[F, Response[F]]],
-)(implicit F: ConcurrentEffect[F])
-    extends JettyResponse.Listener.Adapter {
+)(implicit F: ConcurrentEffect[F], CS: ContextShift[F])
+    extends JettyResponse.Listener {
   import ResponseListener.logger
 
   /* Needed to properly propagate client errors */
@@ -87,14 +86,13 @@ private[jetty] final case class ResponseListener[F[_]](
   override def onContent(
       response: JettyResponse,
       content: ByteBuffer,
-      callback: JettyCallback,
   ): Unit = {
     val copy = ByteBuffer.allocate(content.remaining())
     copy.put(content).flip()
     enqueue(Item.Buf(copy)) {
-      case Right(_) => IO(callback.succeeded())
+      case Right(_) => IO.unit
       case Left(e) =>
-        IO(logger.error(e)("Error in asynchronous callback")) >> IO(callback.failed(e))
+        IO(logger.error(e)("Error in asynchronous callback"))
     }
   }
 
@@ -110,11 +108,21 @@ private[jetty] final case class ResponseListener[F[_]](
   // (the request might complete after the response has been entirely received)
   override def onComplete(result: Result): Unit = ()
 
-  private def abort(t: Throwable, response: JettyResponse): Unit =
-    if (!response.abort(t)) // this also aborts the request
-      logger.error(t)("Failed to abort the response")
-    else
-      closeStream()
+  private def abort(t: Throwable, response: JettyResponse): Unit = {
+    import scala.compat.java8.FutureConverters._
+
+    Async
+      .fromFuture(F.delay(response.abort(t).toScala))
+      .runAsync { attempt =>
+        loggingAsyncCallback(logger)(attempt.map { aborted =>
+          if (!aborted)
+            logger.error(t)("Failed to abort the response")
+          else
+            closeStream()
+        })
+      }
+      .unsafeRunSync()
+  }
 
   private def closeStream(): Unit =
     enqueue(Item.Done)(loggingAsyncCallback(logger))
@@ -135,9 +143,9 @@ private[jetty] object ResponseListener {
 
   private val logger = getLogger
 
-  def apply[F[_]](
+  def apply[F[_]: ConcurrentEffect: ContextShift](
       cb: Callback[Resource[F, Response[F]]]
-  )(implicit F: ConcurrentEffect[F]): F[ResponseListener[F]] =
+  ): F[ResponseListener[F]] =
     Queue
       .synchronous[F, Item]
       .map(q => ResponseListener(q, cb))
diff --git a/jetty-client/src/main/scala/org/http4s/jetty/client/StreamRequestContentProvider.scala b/jetty-client/src/main/scala/org/http4s/jetty/client/StreamRequestContentProvider.scala
index 053313bb460..1d8ae579ffd 100644
--- a/jetty-client/src/main/scala/org/http4s/jetty/client/StreamRequestContentProvider.scala
+++ b/jetty-client/src/main/scala/org/http4s/jetty/client/StreamRequestContentProvider.scala
@@ -23,18 +23,18 @@ import cats.effect.concurrent.Semaphore
 import cats.effect.implicits._
 import cats.syntax.all._
 import fs2._
-import org.eclipse.jetty.client.util.DeferredContentProvider
+import org.eclipse.jetty.client.AsyncRequestContent
 import org.eclipse.jetty.util.{Callback => JettyCallback}
 import org.http4s.internal.loggingAsyncCallback
 import org.log4s.getLogger
 
 private[jetty] final case class StreamRequestContentProvider[F[_]](s: Semaphore[F])(implicit
     F: Effect[F]
-) extends DeferredContentProvider {
+) extends AsyncRequestContent {
   import StreamRequestContentProvider.logger
 
-  def write(req: Request[F]): F[Unit] =
-    req.body.chunks
+  def write(body: Stream[F, Byte]): F[Unit] =
+    body.chunks
       .through(pipe)
       .compile
       .drain
@@ -43,13 +43,11 @@ private[jetty] final case class StreamRequestContentProvider[F[_]](s: Semaphore[
   private val pipe: Pipe[F, Chunk[Byte], Unit] =
     _.evalMap { c =>
       write(c)
-        .ensure(new Exception("something terrible has happened"))(res => res)
-        .map(_ => ())
     }
 
-  private def write(chunk: Chunk[Byte]): F[Boolean] =
+  private def write(chunk: Chunk[Byte]): F[Unit] =
     s.acquire
-      .map(_ => super.offer(chunk.toByteBuffer, callback))
+      .map(_ => super.write(chunk.toByteBuffer, callback))
 
   private val callback: JettyCallback = new JettyCallback {
     override def succeeded(): Unit =
@@ -61,5 +59,6 @@ private[jetty] object StreamRequestContentProvider {
   private val logger = getLogger
 
   def apply[F[_]]()(implicit F: ConcurrentEffect[F]): F[StreamRequestContentProvider[F]] =
-    Semaphore[F](1).map(StreamRequestContentProvider(_))
+    Semaphore[F](1).map(new StreamRequestContentProvider(_))
+
 }
diff --git a/jetty-server/src/main/scala/org/http4s/jetty/server/JettyBuilder.scala b/jetty-server/src/main/scala/org/http4s/jetty/server/JettyBuilder.scala
index 40cc8f768de..804e29dce61 100644
--- a/jetty-server/src/main/scala/org/http4s/jetty/server/JettyBuilder.scala
+++ b/jetty-server/src/main/scala/org/http4s/jetty/server/JettyBuilder.scala
@@ -20,15 +20,15 @@ package server
 
 import cats.effect._
 import cats.syntax.all._
+import org.eclipse.jetty.ee8.servlet.FilterHolder
+import org.eclipse.jetty.ee8.servlet.ServletContextHandler
+import org.eclipse.jetty.ee8.servlet.ServletHolder
 import org.eclipse.jetty.http2.server.HTTP2CServerConnectionFactory
 import org.eclipse.jetty.server.HttpConfiguration
 import org.eclipse.jetty.server.HttpConnectionFactory
 import org.eclipse.jetty.server.ServerConnector
 import org.eclipse.jetty.server.handler.StatisticsHandler
 import org.eclipse.jetty.server.{Server => JServer}
-import org.eclipse.jetty.servlet.FilterHolder
-import org.eclipse.jetty.servlet.ServletContextHandler
-import org.eclipse.jetty.servlet.ServletHolder
 import org.eclipse.jetty.util.ssl.SslContextFactory
 import org.eclipse.jetty.util.thread.ThreadPool
 import org.http4s.jetty.server.JettyBuilder._
diff --git a/jetty-server/src/main/scala/org/http4s/jetty/server/JettyLifeCycle.scala b/jetty-server/src/main/scala/org/http4s/jetty/server/JettyLifeCycle.scala
index 59a76836b4c..280243959b5 100644
--- a/jetty-server/src/main/scala/org/http4s/jetty/server/JettyLifeCycle.scala
+++ b/jetty-server/src/main/scala/org/http4s/jetty/server/JettyLifeCycle.scala
@@ -55,36 +55,40 @@ private[jetty] object JettyLifeCycle {
     * internally, e.g. due to some internal error occurring.
     */
   private[this] def stopLifeCycle[F[_]](lifeCycle: LifeCycle)(implicit F: Async[F]): F[Unit] =
-    F.async[Unit] { cb =>
-      lifeCycle.addLifeCycleListener(
-        new LifeCycle.Listener {
-          override def lifeCycleStopped(a: LifeCycle): Unit =
-            cb(Right(()))
-          override def lifeCycleFailure(a: LifeCycle, error: Throwable): Unit =
-            cb(Left(error))
-        }
-      )
+    F.asyncF[Unit] { cb =>
+      F.defer {
+        val listener =
+          new LifeCycle.Listener {
+            override def lifeCycleStopped(a: LifeCycle): Unit =
+              cb(Right(()))
+
+            override def lifeCycleFailure(a: LifeCycle, error: Throwable): Unit =
+              cb(Left(error))
+          }
+        lifeCycle.addEventListener(listener)
 
-      // In the general case, it is not sufficient to merely call stop(). For
-      // example, the concrete implementation of stop() for the canonical
-      // Jetty Server instance will shortcut to a `return` call taking no
-      // action if the server is "stopping". This method _can't_ return until
-      // we are _actually stopped_, so we have to check three different states
-      // here.
+        // In the general case, it is not sufficient to merely call stop(). For
+        // example, the concrete implementation of stop() for the canonical
+        // Jetty Server instance will shortcut to a `return` call taking no
+        // action if the server is "stopping". This method _can't_ return until
+        // we are _actually stopped_, so we have to check three different states
+        // here.
 
-      if (lifeCycle.isStopped) {
-        // If the first case, we are already stopped, so our listener won't be
-        // called and we just return.
-        cb(Right(()))
-      } else if (lifeCycle.isStopping()) {
-        // If it is stopping, we need to wait for our listener to get invoked.
-        ()
-      } else {
-        // If it is neither stopped nor stopping, we need to request a stop
-        // and then wait for the event. It is imperative that we add the
-        // listener beforehand here. Otherwise we have some very annoying race
-        // conditions.
-        lifeCycle.stop()
+        if (lifeCycle.isStopped) {
+          // If the first case, we are already stopped, so our listener won't be
+          // called and we just return.
+          cb(Right(()))
+        } else if (lifeCycle.isStopping()) {
+          // If it is stopping, we need to wait for our listener to get invoked.
+          ()
+        } else {
+          // If it is neither stopped nor stopping, we need to request a stop
+          // and then wait for the event. It is imperative that we add the
+          // listener beforehand here. Otherwise we have some very annoying race
+          // conditions.
+          lifeCycle.stop()
+        }
+        F.delay(lifeCycle.removeEventListener(listener)).void
       }
     }
 
@@ -95,51 +99,55 @@ private[jetty] object JettyLifeCycle {
     * (or starting) this will fail.
     */
   private[this] def startLifeCycle[F[_]](lifeCycle: LifeCycle)(implicit F: Async[F]): F[Unit] =
-    F.async[Unit] { cb =>
-      lifeCycle.addLifeCycleListener(
-        new LifeCycle.Listener {
-          override def lifeCycleStarted(a: LifeCycle): Unit =
-            cb(Right(()))
-          override def lifeCycleFailure(a: LifeCycle, error: Throwable): Unit =
-            cb(Left(error))
-        }
-      )
+    F.asyncF[Unit] { cb =>
+      F.defer {
+        val listener =
+          new LifeCycle.Listener {
+            override def lifeCycleStarted(a: LifeCycle): Unit =
+              cb(Right(()))
+
+            override def lifeCycleFailure(a: LifeCycle, error: Throwable): Unit =
+              cb(Left(error))
+          }
+        lifeCycle.addEventListener(listener)
 
-      // Sanity check to ensure the LifeCycle component is not already
-      // started. A couple of notes here.
-      //
-      // - There is _always_ going to be a small chance of a race condition
-      //   here in the final branch where we invoke `lifeCycle.start()` _if_
-      //   something else has a reference to the `LifeCycle`
-      //   value. Thankfully, unlike the stopLifeCycle function, this is
-      //   completely in the control of the caller. As long as the caller
-      //   doesn't leak the reference (or call .start() themselves) nothing
-      //   internally to Jetty should ever invoke .start().
-      // - Jetty components allow for reuse in many cases, unless the
-      //   .destroy() method is invoked (and the particular type implements
-      //   `Destroyable`, it's not part of `LifeCycle`). Jetty uses this for
-      //   "soft" resets of the `LifeCycle` component. Thus it is possible
-      //   that this `LifeCycle` component has been started before, though I
-      //   don't recommend this and we don't (at this time) do that in the
-      //   http4s codebase.
-      if (lifeCycle.isStarted) {
-        cb(
-          Left(
-            new IllegalStateException(
-              "Attempting to start Jetty LifeCycle component, but it is already started."
+        // Sanity check to ensure the LifeCycle component is not already
+        // started. A couple of notes here.
+        //
+        // - There is _always_ going to be a small chance of a race condition
+        //   here in the final branch where we invoke `lifeCycle.start()` _if_
+        //   something else has a reference to the `LifeCycle`
+        //   value. Thankfully, unlike the stopLifeCycle function, this is
+        //   completely in the control of the caller. As long as the caller
+        //   doesn't leak the reference (or call .start() themselves) nothing
+        //   internally to Jetty should ever invoke .start().
+        // - Jetty components allow for reuse in many cases, unless the
+        //   .destroy() method is invoked (and the particular type implements
+        //   `Destroyable`, it's not part of `LifeCycle`). Jetty uses this for
+        //   "soft" resets of the `LifeCycle` component. Thus it is possible
+        //   that this `LifeCycle` component has been started before, though I
+        //   don't recommend this and we don't (at this time) do that in the
+        //   http4s codebase.
+        if (lifeCycle.isStarted) {
+          cb(
+            Left(
+              new IllegalStateException(
+                "Attempting to start Jetty LifeCycle component, but it is already started."
+              )
             )
           )
-        )
-      } else if (lifeCycle.isStarting) {
-        cb(
-          Left(
-            new IllegalStateException(
-              "Attempting to start Jetty LifeCycle component, but it is already starting."
+        } else if (lifeCycle.isStarting) {
+          cb(
+            Left(
+              new IllegalStateException(
+                "Attempting to start Jetty LifeCycle component, but it is already starting."
+              )
             )
           )
-        )
-      } else {
-        lifeCycle.start()
+        } else {
+          lifeCycle.start()
+        }
+        F.delay(lifeCycle.removeEventListener(listener)).void
       }
     }
 }
diff --git a/jetty-server/src/test/scala/org/http4s/jetty/server/Issue454.scala b/jetty-server/src/test/scala/org/http4s/jetty/server/Issue454.scala
index ebd2fc6f742..106997d690f 100644
--- a/jetty-server/src/test/scala/org/http4s/jetty/server/Issue454.scala
+++ b/jetty-server/src/test/scala/org/http4s/jetty/server/Issue454.scala
@@ -20,12 +20,12 @@ package server
 
 import cats.effect.ContextShift
 import cats.effect.IO
+import org.eclipse.jetty.ee8.servlet.ServletContextHandler
+import org.eclipse.jetty.ee8.servlet.ServletHolder
 import org.eclipse.jetty.server.HttpConfiguration
 import org.eclipse.jetty.server.HttpConnectionFactory
 import org.eclipse.jetty.server.Server
 import org.eclipse.jetty.server.ServerConnector
-import org.eclipse.jetty.servlet.ServletContextHandler
-import org.eclipse.jetty.servlet.ServletHolder
 import org.http4s.dsl.io._
 import org.http4s.server.DefaultServiceErrorHandler
 import org.http4s.servlet.AsyncHttp4sServlet
diff --git a/project/Http4sPlugin.scala b/project/Http4sPlugin.scala
index ac423aa73d1..aa49a533c21 100644
--- a/project/Http4sPlugin.scala
+++ b/project/Http4sPlugin.scala
@@ -24,9 +24,9 @@ object Http4sPlugin extends AutoPlugin {
 
   override def requires = Http4sOrgPlugin
 
-  val scala_213 = "2.13.8"
-  val scala_212 = "2.12.15"
-  val scala_3 = "3.0.2"
+  val scala_213 = "2.13.11"
+  val scala_212 = "2.12.18"
+  val scala_3 = "3.3.4"
 
   override lazy val globalSettings = Seq(
     isCi := githubIsWorkflowBuild.value
@@ -154,7 +154,8 @@ object Http4sPlugin extends AutoPlugin {
     val javaWebSocket = "1.5.3"
     val jawn = "1.3.2"
     val jawnFs2 = "1.2.1"
-    val jetty = "9.4.46.v20220331"
+//    val jetty = "9.4.46.v20220331"
+    val jetty = "12.0.15"
     val keypool = "0.3.6"
     val literally = "1.0.2"
     val logback = "1.2.6"
@@ -172,15 +173,19 @@ object Http4sPlugin extends AutoPlugin {
     val quasiquotes = "2.1.0"
     val scalacheck = "1.15.4"
     val scalacheckEffect = "1.0.3"
+    val scalacCompatAnnotation = "0.1.4"
+    val scalaJava8Compat = "1.0.2"
     val scalatags = "0.10.0"
     val scalaXml = "2.1.0"
     val scodecBits = "1.1.29"
-    val servlet = "3.1.0"
+    val servlet = "4.0.1"
     val slf4j = "1.7.36"
     val tomcat = "9.0.62"
     val treehugger = "0.4.4"
     val twirl = "1.4.2"
     val vault = "2.2.1"
+
+    val scalafix = "0.11.0"
   }
 
   lazy val asyncHttpClient = "org.asynchttpclient" % "async-http-client" % V.asyncHttpClient
@@ -218,10 +223,10 @@ object Http4sPlugin extends AutoPlugin {
   lazy val jawnPlay = "org.typelevel" %% "jawn-play" % V.jawn
   lazy val jettyClient = "org.eclipse.jetty" % "jetty-client" % V.jetty
   lazy val jettyHttp = "org.eclipse.jetty" % "jetty-http" % V.jetty
-  lazy val jettyHttp2Server = "org.eclipse.jetty.http2" % "http2-server" % V.jetty
-  lazy val jettyRunner = "org.eclipse.jetty" % "jetty-runner" % V.jetty
+  lazy val jettyHttp2Server = "org.eclipse.jetty.http2" % "jetty-http2-server" % V.jetty
   lazy val jettyServer = "org.eclipse.jetty" % "jetty-server" % V.jetty
-  lazy val jettyServlet = "org.eclipse.jetty" % "jetty-servlet" % V.jetty
+  lazy val jettyRunner = "org.eclipse.jetty.ee8" % "jetty-ee8-runner" % V.jetty
+  lazy val jettyServlet = "org.eclipse.jetty.ee8" % "jetty-ee8-servlet" % V.jetty
   lazy val jettyUtil = "org.eclipse.jetty" % "jetty-util" % V.jetty
   lazy val keypool = "org.typelevel" %% "keypool" % V.keypool
   lazy val literally = "org.typelevel" %% "literally" % V.literally
@@ -246,7 +251,10 @@ object Http4sPlugin extends AutoPlugin {
   lazy val scalacheck = "org.scalacheck" %% "scalacheck" % V.scalacheck
   lazy val scalacheckEffect = "org.typelevel" %% "scalacheck-effect" % V.scalacheckEffect
   lazy val scalacheckEffectMunit = "org.typelevel" %% "scalacheck-effect-munit" % V.scalacheckEffect
+  lazy val scalacCompatAnnotation =
+    "org.typelevel" %% "scalac-compat-annotation" % V.scalacCompatAnnotation
   def scalaReflect(sv: String) = "org.scala-lang" % "scala-reflect" % sv
+  lazy val scalaJava8Compat = "org.scala-lang.modules" %% "scala-java8-compat" % V.scalaJava8Compat
   lazy val scalatagsApi = "com.lihaoyi" %% "scalatags" % V.scalatags
   lazy val scalaXml = "org.scala-lang.modules" %% "scala-xml" % V.scalaXml
   lazy val scodecBits = "org.scodec" %% "scodec-bits" % V.scodecBits
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 4367489bbff..557df6af6b9 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,9 +1,11 @@
 libraryDependencies += "ch.qos.logback" % "logback-classic" % "1.2.11"
 
+addDependencyTreePlugin
+
 // https://github.com/coursier/coursier/issues/450
 classpathTypes += "maven-plugin"
 
-addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.10.0")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.11.0")
 addSbtPlugin("com.earldouglas" % "xsbt-web-plugin" % "4.2.4")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.11.0")
 addSbtPlugin("com.github.sbt" % "sbt-unidoc" % "0.5.0")
diff --git a/scalafix-internal/rules/src/main/scala-2/fix/GeneralLinters.scala b/scalafix-internal/rules/src/main/scala-2/fix/GeneralLinters.scala
index ac0dd2d2e4c..a1d386c6224 100644
--- a/scalafix-internal/rules/src/main/scala-2/fix/GeneralLinters.scala
+++ b/scalafix-internal/rules/src/main/scala-2/fix/GeneralLinters.scala
@@ -40,7 +40,7 @@ class GeneralLinters extends SemanticRule("Http4sGeneralLinters") {
 
   def noNonFinalCaseClass(implicit doc: SemanticDocument) =
     doc.tree.collect {
-      case c @ Defn.Class(mods, _, _, _, _)
+      case c @ Defn.Class.After_4_6_0(mods, _, _, _, _)
           if mods.exists(_.is[Mod.Case]) && !mods.exists(mod =>
             (mod.is[Mod.Final] | mod.is[Mod.Sealed] | mod.is[Mod.Private])
           ) && !c.isDescendentOf[Defn.Def] && !c.isDescendentOf[Defn.Val] =>
@@ -49,17 +49,17 @@ class GeneralLinters extends SemanticRule("Http4sGeneralLinters") {
 
   def leakingSealedHierarchy(implicit doc: SemanticDocument) = {
     def doCheck(t: Tree, mods: List[Mod], inits: List[Init]): Patch = inits.collect {
-      case Init(typ, _, _) if typ.symbol.info.exists(_.isSealed) =>
+      case Init.After_4_6_0(typ, _, _) if typ.symbol.info.exists(_.isSealed) =>
         if (!mods.exists(mod => (mod.is[Mod.Final] | mod.is[Mod.Sealed] | mod.is[Mod.Private]))) {
           Patch.lint(LeakingSealedHierarchy(t))
         } else Patch.empty
     }.asPatch
 
     doc.tree.collect {
-      case t @ Defn.Class(mods, _, _, _, Template(_, inits, _, _))
+      case t @ Defn.Class.After_4_6_0(mods, _, _, _, Template.Initial(_, inits, _, _))
           if !t.isDescendentOf[Defn.Def] && !t.isDescendentOf[Defn.Val] =>
         doCheck(t, mods, inits)
-      case t @ Defn.Trait(mods, _, _, _, Template(_, inits, _, _))
+      case t @ Defn.Trait.After_4_6_0(mods, _, _, _, Template.Initial(_, inits, _, _))
           if !t.isDescendentOf[Defn.Def] && !t.isDescendentOf[Defn.Val] =>
         doCheck(t, mods, inits)
     }.asPatch
@@ -67,7 +67,7 @@ class GeneralLinters extends SemanticRule("Http4sGeneralLinters") {
 
   def nonValidatingCopyConstructor(implicit doc: SemanticDocument) =
     doc.tree.collect {
-      case c @ Defn.Class(mods, _, _, Ctor.Primary(ctorMods, _, _), _)
+      case c @ Defn.Class.After_4_6_0(mods, _, _, Ctor.Primary.After_4_6_0(ctorMods, _, _), _)
           if mods.exists(_.is[Mod.Case]) && ctorMods
             .exists(_.is[Mod.Private]) && !mods.exists(_.is[Mod.Abstract]) =>
         Patch.lint(NonValidatingCopyConstructor(c))
diff --git a/scalafix-internal/rules/src/main/scala-2/fix/UseLiteralsSyntax.scala b/scalafix-internal/rules/src/main/scala-2/fix/UseLiteralsSyntax.scala
index f6c7fc900c7..4ecf8a750aa 100644
--- a/scalafix-internal/rules/src/main/scala-2/fix/UseLiteralsSyntax.scala
+++ b/scalafix-internal/rules/src/main/scala-2/fix/UseLiteralsSyntax.scala
@@ -23,12 +23,12 @@ import scala.meta._
 class UseLiteralsSyntax extends SemanticRule("Http4sUseLiteralsSyntax") {
   override def fix(implicit doc: SemanticDocument): Patch =
     doc.tree.collect {
-      case t @ Term.Apply(
+      case t @ Term.Apply.Initial(
             Uri_unsafeFromString_M(_),
             List(lit @ Lit.String(_))
           ) =>
         Patch.replaceTree(t, s"uri$lit") + importLiteralsIfNeeded
-      case t @ Term.Apply(
+      case t @ Term.Apply.Initial(
             Path_unsafeFromString_M(_),
             List(lit @ Lit.String(_))
           ) =>
diff --git a/scalafix-internal/tests/src/test/scala-2/fix/RuleSuite.scala b/scalafix-internal/tests/src/test/scala-2/fix/RuleSuite.scala
index 5754bae5bb8..63e5fad6c7d 100644
--- a/scalafix-internal/tests/src/test/scala-2/fix/RuleSuite.scala
+++ b/scalafix-internal/tests/src/test/scala-2/fix/RuleSuite.scala
@@ -1,8 +1,8 @@
 package fix
 
-import org.scalatest.FunSpecLike
+import org.scalatest.funspec.AnyFunSpecLike
 import scalafix.testkit.AbstractSemanticRuleSuite
 
-class RuleSuite extends AbstractSemanticRuleSuite with FunSpecLike {
+class RuleSuite extends AbstractSemanticRuleSuite with AnyFunSpecLike {
   runAllTests()
 }
diff --git a/scalafix/build.sbt b/scalafix/build.sbt
index 9923875f285..6c65db2779d 100644
--- a/scalafix/build.sbt
+++ b/scalafix/build.sbt
@@ -1,4 +1,5 @@
 lazy val V = _root_.scalafix.sbt.BuildInfo
+lazy val scalafixVersion = V.scalafixVersion
 lazy val outputVersion = "0.22.7"
 inThisBuild(
   List(
@@ -40,7 +41,7 @@ skip in publish := true
 
 lazy val rules = project.settings(
   moduleName := "http4s-scalafix",
-  libraryDependencies += "ch.epfl.scala" %% "scalafix-core" % V.scalafixVersion
+  libraryDependencies += "ch.epfl.scala" %% "scalafix-core" % scalafixVersion,
 )
   .settings(scalafixSettings)
 
@@ -75,7 +76,7 @@ lazy val output = project.settings(
 lazy val tests = project
   .settings(
     skip in publish := true,
-    libraryDependencies += "ch.epfl.scala" % "scalafix-testkit" % V.scalafixVersion % Test cross CrossVersion.full,
+    libraryDependencies += "ch.epfl.scala" % "scalafix-testkit" % scalafixVersion % Test cross CrossVersion.full,
     Compile / compile :=
       (Compile / compile).dependsOn(input / Compile / compile).value,
     scalafixTestkitOutputSourceDirectories :=
diff --git a/scalafix/project/build.properties b/scalafix/project/build.properties
index 0b2e09c5ac9..c8fcab543a9 100644
--- a/scalafix/project/build.properties
+++ b/scalafix/project/build.properties
@@ -1 +1 @@
-sbt.version=1.4.7
+sbt.version=1.6.2
diff --git a/scalafix/project/plugins.sbt b/scalafix/project/plugins.sbt
index 164753b945c..853f6cf2682 100644
--- a/scalafix/project/plugins.sbt
+++ b/scalafix/project/plugins.sbt
@@ -1,5 +1,5 @@
 resolvers += Resolver.sonatypeRepo("releases")
 
-addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.10.0")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.11.0")
 addSbtPlugin("com.dwijnand" % "sbt-dynver" % "4.0.0")
 addSbtPlugin("com.jsuereth" % "sbt-pgp" % "2.0.1")
diff --git a/scalafix/tests/src/test/scala/fix/RuleSuite.scala b/scalafix/tests/src/test/scala/fix/RuleSuite.scala
index 04566e69440..f396eec882b 100644
--- a/scalafix/tests/src/test/scala/fix/RuleSuite.scala
+++ b/scalafix/tests/src/test/scala/fix/RuleSuite.scala
@@ -16,9 +16,9 @@
 
 package fix
 
-import org.scalatest.FunSpecLike
+import org.scalatest.funspec.AnyFunSpecLike
 import scalafix.testkit.AbstractSemanticRuleSuite
 
-class RuleSuite extends AbstractSemanticRuleSuite with FunSpecLike {
+class RuleSuite extends AbstractSemanticRuleSuite with AnyFunSpecLike {
   runAllTests()
 }
diff --git a/server/src/main/scala/org/http4s/server/middleware/CORS.scala b/server/src/main/scala/org/http4s/server/middleware/CORS.scala
index f629b4728b9..b21d85cd64d 100644
--- a/server/src/main/scala/org/http4s/server/middleware/CORS.scala
+++ b/server/src/main/scala/org/http4s/server/middleware/CORS.scala
@@ -29,8 +29,8 @@ import org.http4s.headers._
 import org.http4s.syntax.header._
 import org.log4s.getLogger
 import org.typelevel.ci._
+import org.typelevel.scalaccompat.annotation._
 
-import scala.annotation.nowarn
 import scala.concurrent.duration._
 import scala.util.hashing.MurmurHash3
 
@@ -195,7 +195,7 @@ object CORS {
     "Depends on a deficient `CORSConfig`. See https://github.com/http4s/http4s/security/advisories/GHSA-52cf-226f-rhr6. If config.anyOrigin is true and config.allowCredentials is true, then the `Access-Control-Allow-Credentials` header will be suppressed starting with 0.22.3.",
     "0.21.27",
   )
-  @nowarn("cat=deprecation")
+  @nowarn212("cat=deprecation")
   def apply[F[_], G[_]](http: Http[F, G], config: CORSConfig = CORSConfig.default)(implicit
       F: Applicative[F]
   ): Http[F, G] = {
diff --git a/servlet/src/test/scala/org/http4s/servlet/TestEclipseServer.scala b/servlet/src/test/scala/org/http4s/servlet/TestEclipseServer.scala
index 0f86d2b9c88..82756565f3d 100644
--- a/servlet/src/test/scala/org/http4s/servlet/TestEclipseServer.scala
+++ b/servlet/src/test/scala/org/http4s/servlet/TestEclipseServer.scala
@@ -18,12 +18,12 @@ package org.http4s.servlet
 
 import cats.effect.IO
 import cats.effect.Resource
+import org.eclipse.jetty.ee8.servlet.ServletContextHandler
+import org.eclipse.jetty.ee8.servlet.ServletHolder
 import org.eclipse.jetty.server.HttpConfiguration
 import org.eclipse.jetty.server.HttpConnectionFactory
 import org.eclipse.jetty.server.ServerConnector
 import org.eclipse.jetty.server.{Server => EclipseServer}
-import org.eclipse.jetty.servlet.ServletContextHandler
-import org.eclipse.jetty.servlet.ServletHolder
 
 import javax.servlet.Servlet