diff --git a/blaze-core/src/main/scala/org/http4s/blazecore/util/Http2Writer.scala b/blaze-core/src/main/scala/org/http4s/blazecore/util/Http2Writer.scala
index 64377bbee..a0d6377ca 100644
--- a/blaze-core/src/main/scala/org/http4s/blazecore/util/Http2Writer.scala
+++ b/blaze-core/src/main/scala/org/http4s/blazecore/util/Http2Writer.scala
@@ -29,6 +29,7 @@ import org.http4s.blaze.pipeline.TailStage
 
 import scala.concurrent._
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http4s] class Http2Writer[F[_]](
     tail: TailStage[StreamFrame],
     private var headers: Headers,
diff --git a/blaze-server/src/main/scala/org/http4s/blaze/server/BlazeServerBuilder.scala b/blaze-server/src/main/scala/org/http4s/blaze/server/BlazeServerBuilder.scala
index 11f7d9831..83823d452 100644
--- a/blaze-server/src/main/scala/org/http4s/blaze/server/BlazeServerBuilder.scala
+++ b/blaze-server/src/main/scala/org/http4s/blaze/server/BlazeServerBuilder.scala
@@ -243,6 +243,7 @@ class BlazeServerBuilder[F[_]] private (
   def withWebSockets(enableWebsockets: Boolean): Self =
     this
 
+  @deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
   def enableHttp2(enabled: Boolean): Self = copy(http2Support = enabled)
 
   def withHttpApp(httpApp: HttpApp[F]): Self =
diff --git a/blaze-server/src/main/scala/org/http4s/blaze/server/Http2NodeStage.scala b/blaze-server/src/main/scala/org/http4s/blaze/server/Http2NodeStage.scala
index 37ae4e6bb..42788195d 100644
--- a/blaze-server/src/main/scala/org/http4s/blaze/server/Http2NodeStage.scala
+++ b/blaze-server/src/main/scala/org/http4s/blaze/server/Http2NodeStage.scala
@@ -46,6 +46,7 @@ import scala.concurrent.duration.Duration
 import scala.concurrent.duration.FiniteDuration
 import scala.util._
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class Http2NodeStage[F[_]](
     streamId: Int,
     timeout: Duration,
diff --git a/blaze-server/src/main/scala/org/http4s/blaze/server/ProtocolSelector.scala b/blaze-server/src/main/scala/org/http4s/blaze/server/ProtocolSelector.scala
index 5ebe21884..32f185eb1 100644
--- a/blaze-server/src/main/scala/org/http4s/blaze/server/ProtocolSelector.scala
+++ b/blaze-server/src/main/scala/org/http4s/blaze/server/ProtocolSelector.scala
@@ -33,11 +33,13 @@ import org.typelevel.vault._
 
 import java.nio.ByteBuffer
 import javax.net.ssl.SSLEngine
+import scala.annotation.nowarn
 import scala.concurrent.ExecutionContext
 import scala.concurrent.duration.Duration
 
 /** Facilitates the use of ALPN when using blaze http2 support */
 private[http4s] object ProtocolSelector {
+  @nowarn("cat=deprecation")
   def apply[F[_]](
       engine: SSLEngine,
       httpApp: HttpApp[F],
diff --git a/examples/src/main/scala/com/example/http4s/blaze/BlazeHttp2Example.scala b/examples/src/main/scala/com/example/http4s/blaze/BlazeHttp2Example.scala
deleted file mode 100644
index ede23cad0..000000000
--- a/examples/src/main/scala/com/example/http4s/blaze/BlazeHttp2Example.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright 2014 http4s.org
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.example.http4s
-package blaze
-
-import cats.effect._
-
-object BlazeHttp2Example extends IOApp {
-  override def run(args: List[String]): IO[ExitCode] =
-    BlazeSslExampleApp.builder[IO].flatMap(_.enableHttp2(true).serve.compile.lastOrError)
-}
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/ByteBufferInputStream.scala b/http/src/main/scala/org/http4s/blaze/http/http2/ByteBufferInputStream.scala
index 78b3db20c..41bcb6843 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/ByteBufferInputStream.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/ByteBufferInputStream.scala
@@ -22,6 +22,7 @@ import java.nio.ByteBuffer
 /** Wrap a `ByteBuffer` in an `InputStream` interface. This is just an adapter to work with the
   * twitter hpack implementation. I would really like to get rid of it.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class ByteBufferInputStream(buffer: ByteBuffer) extends InputStream {
   private[this] var markSize = -1
 
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/Connection.scala b/http/src/main/scala/org/http4s/blaze/http/http2/Connection.scala
index f1cce195d..80b412ce6 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/Connection.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/Connection.scala
@@ -23,6 +23,7 @@ import scala.concurrent.Future
 import scala.concurrent.duration.Duration
 
 /** Representation of the HTTP connection or session */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait Connection {
 
   /** An estimate for the current quality of the connection
@@ -78,6 +79,7 @@ private trait Connection {
   def onClose: Future[Unit]
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[blaze] object Connection {
   sealed abstract class State extends Product with Serializable {
     final def closing: Boolean = !running
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/ConnectionImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/ConnectionImpl.scala
index da9ff7b0c..0354f93c8 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/ConnectionImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/ConnectionImpl.scala
@@ -35,6 +35,7 @@ import scala.util.{Failure, Success}
   *   the TailStage needs to be ready to go as this session will start reading from the channel
   *   immediately.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class ConnectionImpl(
     tailStage: TailStage[ByteBuffer],
     val localSettings: Http2Settings,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/DefaultFlowStrategy.scala b/http/src/main/scala/org/http4s/blaze/http/http2/DefaultFlowStrategy.scala
index a30954015..b5fe5fcbc 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/DefaultFlowStrategy.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/DefaultFlowStrategy.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2
 
 import org.http4s.blaze.http.http2.FlowStrategy.Increment
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 final class DefaultFlowStrategy(localSettings: Http2Settings) extends FlowStrategy {
   override def checkSession(session: SessionFlowControl): Int =
     check(
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/FlowStrategy.scala b/http/src/main/scala/org/http4s/blaze/http/http2/FlowStrategy.scala
index cbc0188ed..a12f4f075 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/FlowStrategy.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/FlowStrategy.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.http.http2.FlowStrategy.Increment
   *
   * A `FlowStrategy` will be shared among many sessions.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 trait FlowStrategy {
 
   /** Decide if the session window needs to send a WINDOW_UPDATE frame
@@ -52,6 +53,7 @@ trait FlowStrategy {
   def checkStream(stream: StreamFlowWindow): Increment
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object FlowStrategy {
   // Make the object private to restrict construction of
   // `Increment`s to the `makeIncrement` method
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/FrameDecoder.scala b/http/src/main/scala/org/http4s/blaze/http/http2/FrameDecoder.scala
index 46cd8a3c3..0d04b3dde 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/FrameDecoder.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/FrameDecoder.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.http.http2.bits.{Flags, Masks}
 
 /* The job of the Http2FrameDecoder is to slice the ByteBuffers. It does
    not attempt to decode headers or perform any size limiting operations */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class FrameDecoder(localSettings: Http2Settings, listener: FrameListener) {
   import bits._
   import FrameDecoder._
@@ -310,6 +311,7 @@ private class FrameDecoder(localSettings: Http2Settings, listener: FrameListener
       listener.onContinuationFrame(streamId, Flags.END_HEADERS(flags), buffer.slice())
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object FrameDecoder {
 
   /** Get the length field of the frame, consuming the bytes from the buffer.
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/FrameEncoder.scala b/http/src/main/scala/org/http4s/blaze/http/http2/FrameEncoder.scala
index 1a0413c48..e13957ebb 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/FrameEncoder.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/FrameEncoder.scala
@@ -23,6 +23,7 @@ import org.http4s.blaze.util.BufferTools
 import scala.collection.mutable.ArrayBuffer
 
 /** A more humane interface for writing HTTP messages. */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class FrameEncoder(remoteSettings: Http2Settings, headerEncoder: HeaderEncoder) {
   // Just a shortcut
   private[this] def maxFrameSize: Int = remoteSettings.maxFrameSize
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/FrameListener.scala b/http/src/main/scala/org/http4s/blaze/http/http2/FrameListener.scala
index 4d66c722a..d7577de36 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/FrameListener.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/FrameListener.scala
@@ -30,6 +30,7 @@ import Http2Settings.Setting
   * is 4 bytes long and the [[FrameListener]] would be expected to signal an error if the window
   * increment was 0 or the update was for an idle stream.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait FrameListener {
 
   /** Determine whether we are in the midst of a sequence of header and header continuation frames
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/FrameSerializer.scala b/http/src/main/scala/org/http4s/blaze/http/http2/FrameSerializer.scala
index 99c96f86b..32b29c8b6 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/FrameSerializer.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/FrameSerializer.scala
@@ -22,6 +22,7 @@ import java.nio.charset.StandardCharsets
 import org.http4s.blaze.http.http2.Http2Settings.Setting
 import org.http4s.blaze.util.BufferTools
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] object FrameSerializer {
   import bits._
 
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListener.scala b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListener.scala
index 14cc3cb28..81b3819aa 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListener.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListener.scala
@@ -33,6 +33,7 @@ import Http2Exception.PROTOCOL_ERROR
   * @note
   *   This class is not 'thread safe' and should be treated accordingly.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private abstract class HeaderAggregatingFrameListener(
     localSettings: Http2Settings,
     headerDecoder: HeaderDecoder
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderDecoder.scala b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderDecoder.scala
index 4add9dfc2..4b1648f85 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderDecoder.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderDecoder.scala
@@ -38,6 +38,7 @@ import scala.util.control.NonFatal
   * @param maxTableSize
   *   maximum compression table to maintain
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class HeaderDecoder(
     maxHeaderListSize: Int,
     discardOverflowHeaders: Boolean,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderEncoder.scala b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderEncoder.scala
index 087a0c224..78e288501 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/HeaderEncoder.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/HeaderEncoder.scala
@@ -29,6 +29,7 @@ import com.twitter.hpack.Encoder
   * @param initialMaxTableSize
   *   maximum HPACK table size the peer will allow.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class HeaderEncoder(initialMaxTableSize: Int) {
   private[this] val encoder = new Encoder(initialMaxTableSize)
   private[this] val os = new ByteArrayOutputStream(1024)
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/Http2Exception.scala b/http/src/main/scala/org/http4s/blaze/http/http2/Http2Exception.scala
index 95251ea79..2aed6e95c 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/Http2Exception.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/Http2Exception.scala
@@ -21,6 +21,7 @@ import java.nio.charset.StandardCharsets.UTF_8
 import scala.collection.mutable
 import scala.util.control.NoStackTrace
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 sealed abstract class Http2Exception(msg: String)
     extends Exception(msg)
     with NoStackTrace
@@ -61,12 +62,15 @@ sealed abstract class Http2Exception(msg: String)
   final def msgBuffer(): ByteBuffer = ByteBuffer.wrap(msg.getBytes(UTF_8))
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 final case class Http2StreamException(stream: Int, code: Long, msg: String)
     extends Http2Exception(msg)
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 final case class Http2SessionException(code: Long, msg: String) extends Http2Exception(msg)
 
 ///////////////////// HTTP/2.0 Errors //////////////////////////////
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object Http2Exception {
   final class ErrorGenerator private[http2] (val code: Long, val name: String) {
 
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/Http2Settings.scala b/http/src/main/scala/org/http4s/blaze/http/http2/Http2Settings.scala
index bbb2593f8..2eb2b8538 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/Http2Settings.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/Http2Settings.scala
@@ -27,6 +27,7 @@ import scala.collection.mutable
   * @see
   *   https://tools.ietf.org/html/rfc7540#section-6.5.2, where the doc strings were obtained.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 sealed abstract class Http2Settings {
 
   /** Allows the sender to inform the remote endpoint of the maximum size of the header compression
@@ -82,6 +83,7 @@ sealed abstract class Http2Settings {
 }
 
 /** Immutable representation of [[Http2Settings]] for configuring clients and servers */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 case class ImmutableHttp2Settings(
     headerTableSize: Int,
     initialWindowSize: Int,
@@ -91,6 +93,7 @@ case class ImmutableHttp2Settings(
     maxHeaderListSize: Int
 ) extends Http2Settings
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object Http2Settings {
   type SettingValue = Int
 
@@ -192,6 +195,7 @@ object Http2Settings {
 }
 
 /** Internal mutable representation of the [[Http2Settings]] */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[blaze] final class MutableHttp2Settings private (
     var headerTableSize: Int,
     var initialWindowSize: Int,
@@ -229,6 +233,7 @@ private[blaze] final class MutableHttp2Settings private (
     s"MutableHttp2Settings(${toSeq.mkString(", ")})"
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object MutableHttp2Settings {
   private val logger = getLogger
 
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamState.scala b/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamState.scala
index 8960369d1..9d5ae64a3 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamState.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamState.scala
@@ -21,4 +21,5 @@ package org.http4s.blaze.http.http2
   * @note
   *   this is only a marker trait
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait InboundStreamState extends StreamState
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamStateImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamStateImpl.scala
index cbd58c3bf..5c0db630b 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamStateImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/InboundStreamStateImpl.scala
@@ -16,6 +16,7 @@
 
 package org.http4s.blaze.http.http2
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class InboundStreamStateImpl(
     session: SessionCore,
     val streamId: Int,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamState.scala b/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamState.scala
index 6bb85a4c7..ebc0c2668 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamState.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamState.scala
@@ -25,4 +25,5 @@ package org.http4s.blaze.http.http2
   * @note
   *   this is a marker trait
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait OutboundStreamState extends StreamState
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamStateImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamStateImpl.scala
index 48b515352..6618137fe 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamStateImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/OutboundStreamStateImpl.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import scala.concurrent.Promise
 import scala.concurrent.duration.Duration
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private abstract class OutboundStreamStateImpl(session: SessionCore)
     extends StreamStateImpl(session)
     with OutboundStreamState {
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/PingManager.scala b/http/src/main/scala/org/http4s/blaze/http/http2/PingManager.scala
index e984d965f..ccbba3491 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/PingManager.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/PingManager.scala
@@ -24,6 +24,7 @@ import org.log4s.getLogger
 import scala.concurrent.{Future, Promise}
 import scala.concurrent.duration.Duration
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class PingManager(session: SessionCore) {
   import PingManager._
 
@@ -99,6 +100,7 @@ private class PingManager(session: SessionCore) {
     }
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object PingManager {
   private sealed trait State
 
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/PriorKnowledgeHandshaker.scala b/http/src/main/scala/org/http4s/blaze/http/http2/PriorKnowledgeHandshaker.scala
index 97feee66b..960e774f2 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/PriorKnowledgeHandshaker.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/PriorKnowledgeHandshaker.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.util.{BufferTools, Execution}
 import scala.concurrent.{ExecutionContext, Future}
 
 /** Base type for performing the HTTP/2 prior knowledge handshake */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 abstract class PriorKnowledgeHandshaker[T](localSettings: ImmutableHttp2Settings)
     extends TailStage[ByteBuffer] {
   implicit protected final def ec: ExecutionContext = Execution.trampoline
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/Priority.scala b/http/src/main/scala/org/http4s/blaze/http/http2/Priority.scala
index e14989140..bd678f1db 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/Priority.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/Priority.scala
@@ -16,10 +16,12 @@
 
 package org.http4s.blaze.http.http2
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 sealed trait Priority {
   def isDefined: Boolean
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object Priority {
 
   /** object representing the contents of a PRIORITY frame
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/PseudoHeaders.scala b/http/src/main/scala/org/http4s/blaze/http/http2/PseudoHeaders.scala
index 04c606075..433d0ae0c 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/PseudoHeaders.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/PseudoHeaders.scala
@@ -17,6 +17,7 @@
 package org.http4s.blaze.http.http2
 
 /** HTTP/2 pseudo headers */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object PseudoHeaders {
   // Request pseudo headers
   val Method = ":method"
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/Result.scala b/http/src/main/scala/org/http4s/blaze/http/http2/Result.scala
index b99005f7b..29b418200 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/Result.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/Result.scala
@@ -17,16 +17,20 @@
 package org.http4s.blaze.http.http2
 
 /** Result type of many of the codec methods */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private sealed trait Result extends Product with Serializable
 
 /** Didn't get enough data to decode a full HTTP/2 frame */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private case object BufferUnderflow extends Result
 
 /** Represents the possibility of failure */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private sealed abstract class MaybeError extends Result {
   final def success: Boolean = this == Continue
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object MaybeError {
   def apply(option: Option[Http2Exception]): MaybeError =
     option match {
@@ -35,5 +39,8 @@ private object MaybeError {
     }
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private case object Continue extends MaybeError
+
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final case class Error(err: Http2Exception) extends MaybeError
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/SessionCore.scala b/http/src/main/scala/org/http4s/blaze/http/http2/SessionCore.scala
index 3ce5bc47e..6276ad281 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/SessionCore.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/SessionCore.scala
@@ -23,6 +23,7 @@ import scala.concurrent.duration.Duration
   * 'bag-o-references' so that each component can reference each other. This helps to avoid
   * construction order conflicts.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private abstract class SessionCore {
   // Fields
   def serialExecutor: ExecutionContext
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControl.scala
index 8c2dab75e..96d6a61ee 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControl.scala
@@ -17,6 +17,7 @@
 package org.http4s.blaze.http.http2
 
 /** Flow control representation of a Http2 Session */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 abstract class SessionFlowControl {
 
   /** Create a new [[StreamFlowWindow]] for a stream which will update and check the bounds of the
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControlImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControlImpl.scala
index e45123c7c..5b4ec0179 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControlImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFlowControlImpl.scala
@@ -21,6 +21,7 @@ import org.http4s.blaze.http.http2.Http2Exception.{FLOW_CONTROL_ERROR, PROTOCOL_
 import org.log4s.getLogger
 
 /** Flow control representation of a Http2 Session */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class SessionFlowControlImpl(
     session: SessionCore,
     flowStrategy: FlowStrategy
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFrameListener.scala b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFrameListener.scala
index e9d305272..43e4e92dd 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/SessionFrameListener.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/SessionFrameListener.scala
@@ -28,6 +28,7 @@ import org.http4s.blaze.http.http2.Http2Settings.Setting
   * Concurrency is not controlled by this type; it is expected that thread safety will be managed by
   * the [[ConnectionImpl]].
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class SessionFrameListener(
     session: SessionCore,
     isClient: Boolean,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/SettingsDecoder.scala b/http/src/main/scala/org/http4s/blaze/http/http2/SettingsDecoder.scala
index c7c775ba0..3949464c7 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/SettingsDecoder.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/SettingsDecoder.scala
@@ -25,6 +25,7 @@ import org.http4s.blaze.http.http2.bits.{Flags, FrameTypes}
   * @see
   *   https://tools.ietf.org/html/rfc7540#section-6.5
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[blaze] object SettingsDecoder {
 
   /** Representation of a settings frame
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StageTools.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StageTools.scala
index a58b79b0b..7f7984bc0 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StageTools.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StageTools.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import java.util.Locale
 import scala.collection.mutable.{ArrayBuffer, Builder}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] object StageTools {
   // There are two copies of this because `Growable` moved in Scala
   // 2.13 and we're stuck with the deprecation warning.  It's private
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamFlowWindow.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamFlowWindow.scala
index 48a8dba20..3b3324ff6 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamFlowWindow.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamFlowWindow.scala
@@ -21,6 +21,7 @@ package org.http4s.blaze.http.http2
   * The `StreamFlowWindow` provides the tools for tracking the flow window for both the individual
   * stream and the session that it belongs to.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 abstract class StreamFlowWindow {
 
   /** The flow control manager of the session this stream belongs to */
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamFrame.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamFrame.scala
index 5c11ffa90..3602b76a4 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamFrame.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamFrame.scala
@@ -21,6 +21,7 @@ package http2
 import java.nio.ByteBuffer
 
 /** Types that will be sent down to the Nodes of the Http2 session */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 sealed trait StreamFrame {
   def endStream: Boolean
   def flowBytes: Int
@@ -34,6 +35,7 @@ sealed trait StreamFrame {
   *   actual stream data. The `ByteBuffer` indexes may be modified by the receiver. The `ByteBuffer`
   *   indexes are considered owned by this DataFrame, but its data must not be modified.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 case class DataFrame(endStream: Boolean, data: ByteBuffer) extends StreamFrame {
   def flowBytes: Int = data.remaining()
 }
@@ -47,6 +49,7 @@ case class DataFrame(endStream: Boolean, data: ByteBuffer) extends StreamFrame {
   * @param headers
   *   attached headers
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 case class HeadersFrame(priority: Priority, endStream: Boolean, headers: Headers)
     extends StreamFrame {
   override def flowBytes: Int = 0
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamIdManager.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamIdManager.scala
index 1585389a2..fc3c1101d 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamIdManager.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamIdManager.scala
@@ -16,6 +16,7 @@
 
 package org.http4s.blaze.http.http2
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] object StreamIdManager {
 
   /** Create a new [[StreamIdManager]] */
@@ -32,6 +33,7 @@ private[http2] object StreamIdManager {
 }
 
 /** Tool for tracking stream ids */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class StreamIdManager private (
     isClient: Boolean,
     private var nextInbound: Int,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamManager.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamManager.scala
index e194ea4f8..248c41548 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamManager.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamManager.scala
@@ -24,6 +24,7 @@ import scala.concurrent.Future
   * The `StreamManager` can be thought of as the collection of active streams and some associated
   * helper methods for performing operations relevant to the HTTP/2 protocol.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait StreamManager {
 
   /** Number of active streams */
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamManagerImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamManagerImpl.scala
index a92282794..133f86db1 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamManagerImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamManagerImpl.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.pipeline.{Command, LeafBuilder}
 import scala.collection.mutable.HashMap
 import scala.concurrent.{Future, Promise}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class StreamManagerImpl(
     session: SessionCore,
     inboundStreamBuilder: Option[Int => LeafBuilder[StreamFrame]]
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamState.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamState.scala
index ee470cc08..05f9499a0 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamState.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamState.scala
@@ -22,6 +22,7 @@ import java.nio.ByteBuffer
 
 import org.http4s.blaze.pipeline.HeadStage
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait StreamState extends HeadStage[StreamFrame] with WriteInterest {
 
   /** Whether the `StreamState` is part of the H2 session
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/StreamStateImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/StreamStateImpl.scala
index 927881cd7..e77787aba 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/StreamStateImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/StreamStateImpl.scala
@@ -36,6 +36,7 @@ import scala.concurrent.{Future, Promise}
   *   attempt to enforce the semantics of the HTTP dispatch, specifically it doesn't enforce that
   *   HEADERS come before DATA, etc, and that duty belongs to the streams dispatcher.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private abstract class StreamStateImpl(session: SessionCore) extends StreamState {
   // State associated with the streams inbound data flow
   private[this] val pendingInboundMessages = new util.ArrayDeque[StreamFrame](1)
@@ -346,6 +347,7 @@ private abstract class StreamStateImpl(session: SessionCore) extends StreamState
   }
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object StreamStateImpl {
   // Cache this since it will be a common value
   private val SomeEOF: Some[Throwable] = Some(EOF)
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/WriteController.scala b/http/src/main/scala/org/http4s/blaze/http/http2/WriteController.scala
index b08250190..2c38683bc 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/WriteController.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/WriteController.scala
@@ -25,6 +25,7 @@ import scala.concurrent.Future
 // the boundaries of where one message starts and another begins.
 // This would allow us to prioritize messages (like PING responses).
 /** Generic interface used by HTTP2 types to write data */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait WriteController {
 
   /** Register a [[WriteInterest]] with this listener to be invoked later once it is possible to
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/WriteControllerImpl.scala b/http/src/main/scala/org/http4s/blaze/http/http2/WriteControllerImpl.scala
index 2c8a96606..56d99cea7 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/WriteControllerImpl.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/WriteControllerImpl.scala
@@ -37,6 +37,7 @@ import scala.util.control.NonFatal
   * @param highWaterMark
   *   number of bytes that will trigger a flush.
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private final class WriteControllerImpl(
     session: SessionCore,
     highWaterMark: Int,
@@ -170,6 +171,7 @@ private final class WriteControllerImpl(
   }
 }
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private object WriteControllerImpl {
   private sealed trait State
   private case object Idle extends State
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/WriteInterest.scala b/http/src/main/scala/org/http4s/blaze/http/http2/WriteInterest.scala
index 078737aca..628bde8ad 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/WriteInterest.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/WriteInterest.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import java.nio.ByteBuffer
 
 /** Type that can be polled for the ability to write bytes */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private trait WriteInterest {
 
   /** Invoked by the [[WriteController]] that this `WriteInterest` is registered with.
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/bits.scala b/http/src/main/scala/org/http4s/blaze/http/http2/bits.scala
index 96a148620..610cfe7ca 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/bits.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/bits.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import java.nio.ByteBuffer
 import java.nio.charset.StandardCharsets
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] object bits {
   val LengthFieldSize: Int = 3
   val HeaderSize: Int = 9
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/server/ALPNServerSelector.scala b/http/src/main/scala/org/http4s/blaze/http/http2/server/ALPNServerSelector.scala
index 7a9ba6254..b225aafeb 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/server/ALPNServerSelector.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/server/ALPNServerSelector.scala
@@ -36,6 +36,7 @@ import scala.util.control.NonFatal
   * @param builder
   *   builds the appropriate pipeline based on the negotiated protocol
   */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 final class ALPNServerSelector(
     engine: SSLEngine,
     selector: Set[String] => String,
diff --git a/http/src/main/scala/org/http4s/blaze/http/http2/server/ServerPriorKnowledgeHandshaker.scala b/http/src/main/scala/org/http4s/blaze/http/http2/server/ServerPriorKnowledgeHandshaker.scala
index 07a2dfbca..150931df0 100644
--- a/http/src/main/scala/org/http4s/blaze/http/http2/server/ServerPriorKnowledgeHandshaker.scala
+++ b/http/src/main/scala/org/http4s/blaze/http/http2/server/ServerPriorKnowledgeHandshaker.scala
@@ -25,6 +25,7 @@ import org.http4s.blaze.util.{BufferTools, Execution, StageTools}
 import scala.concurrent.Future
 import scala.util.Failure
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 final class ServerPriorKnowledgeHandshaker(
     localSettings: ImmutableHttp2Settings,
     flowStrategy: FlowStrategy,
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/ByteBufferInputStreamSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/ByteBufferInputStreamSuite.scala
index 8e3610561..41325229f 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/ByteBufferInputStreamSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/ByteBufferInputStreamSuite.scala
@@ -20,6 +20,7 @@ import java.nio.ByteBuffer
 
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class ByteBufferInputStreamSuite extends BlazeTestSuite {
   private def fromByteBuffer(buffer: ByteBuffer): ByteBufferInputStream =
     new ByteBufferInputStream(buffer)
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/CodecUtils.scala b/http/src/test/scala/org/http4s/blaze/http/http2/CodecUtils.scala
index c00767dbc..a5ceaff04 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/CodecUtils.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/CodecUtils.scala
@@ -21,7 +21,9 @@ import java.nio.charset.StandardCharsets
 
 import org.http4s.blaze.util.BufferTools._
 
-private[http2] object CodecUtils {
+@deprecated(
+  "HTTP/2 support is unmaintained and will be removed in a future version.",
+  "0.23.18") private[http2] object CodecUtils {
   def byteData: Array[Byte] =
     "The quick brown fox jumps over the lazy dog".getBytes(StandardCharsets.UTF_8)
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/ConnectionImplSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/ConnectionImplSuite.scala
index 7841d4325..353f3c75c 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/ConnectionImplSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/ConnectionImplSuite.scala
@@ -31,6 +31,7 @@ import scala.concurrent.duration.Duration
 import scala.concurrent.Future
 import scala.util.{Failure, Success}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class ConnectionImplSuite extends BlazeTestSuite {
   private class Ctx {
     lazy val head = new MockByteBufferHeadStage
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/DelayedExecutionContext.scala b/http/src/test/scala/org/http4s/blaze/http/http2/DelayedExecutionContext.scala
index cbdd4e404..624492750 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/DelayedExecutionContext.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/DelayedExecutionContext.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import scala.collection.mutable
 import scala.concurrent.ExecutionContext
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class DelayedExecutionContext extends ExecutionContext {
   private[this] val pending = new mutable.Queue[Runnable]()
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/FrameDecoderSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/FrameDecoderSuite.scala
index 0e99beff8..213fccf08 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/FrameDecoderSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/FrameDecoderSuite.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.http.http2.mocks.MockFrameListener
 import org.http4s.blaze.http.http2.Priority.Dependent
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class FrameDecoderSuite extends BlazeTestSuite {
   def buffer(data: Byte*): ByteBuffer =
     ByteBuffer.wrap(data.toArray)
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/FrameEncoderSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/FrameEncoderSuite.scala
index 4ded7d6e5..4fd97260d 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/FrameEncoderSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/FrameEncoderSuite.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.http.http2.mocks.MockTools
 import org.http4s.blaze.testkit.BlazeTestSuite
 import org.http4s.blaze.util.BufferTools
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class FrameEncoderSuite extends BlazeTestSuite {
   import CodecUtils._
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/FrameSerializerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/FrameSerializerSuite.scala
index 219b3f741..77005aff5 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/FrameSerializerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/FrameSerializerSuite.scala
@@ -29,6 +29,7 @@ import org.http4s.blaze.util.BufferTools._
 import org.scalacheck.Prop._
 import org.scalacheck.{Arbitrary, Gen}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class FrameSerializerSuite extends BlazeTestSuite with ScalaCheckSuite {
   import CodecUtils._
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListenerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListenerSuite.scala
index 01383aada..be367d5df 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListenerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderAggregatingFrameListenerSuite.scala
@@ -23,6 +23,7 @@ import org.http4s.blaze.http.http2.mocks.{MockFrameListener, MockHeaderAggregati
 import org.http4s.blaze.testkit.BlazeTestSuite
 import org.http4s.blaze.util.BufferTools
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class HeaderAggregatingFrameListenerSuite extends BlazeTestSuite {
   import BufferTools._
   import CodecUtils._
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderCodecHelpers.scala b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderCodecHelpers.scala
index 50a98fd45..0a5715051 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderCodecHelpers.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderCodecHelpers.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2
 
 import java.nio.ByteBuffer
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object HeaderCodecHelpers {
   def encodeHeaders(hs: Seq[(String, String)], maxTableSize: Int): ByteBuffer = {
     val enc = new HeaderEncoder(maxTableSize)
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderDecoderSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderDecoderSuite.scala
index c2af12201..8cd6b02f0 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderDecoderSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderDecoderSuite.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import org.http4s.blaze.testkit.BlazeTestSuite
 import org.http4s.blaze.util.BufferTools
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class HeaderDecoderSuite extends BlazeTestSuite {
   private val testHeaders = Seq("foo" -> "bar")
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderEncoderSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderEncoderSuite.scala
index f1e64312d..a4b9b1f8d 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/HeaderEncoderSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/HeaderEncoderSuite.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2
 
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class HeaderEncoderSuite extends BlazeTestSuite {
   private val headers = Seq("foo" -> "bar")
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/Http2ExceptionSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/Http2ExceptionSuite.scala
index 3baac6f9e..1344612af 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/Http2ExceptionSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/Http2ExceptionSuite.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2
 
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class Http2ExceptionSuite extends BlazeTestSuite {
   import Http2Exception._
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/MockSessionFlowControl.scala b/http/src/test/scala/org/http4s/blaze/http/http2/MockSessionFlowControl.scala
index 6f42ece1b..94f749f3c 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/MockSessionFlowControl.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/MockSessionFlowControl.scala
@@ -16,6 +16,7 @@
 
 package org.http4s.blaze.http.http2
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private class MockSessionFlowControl extends SessionFlowControl {
   override def newStreamFlowWindow(streamId: Int): StreamFlowWindow = ???
   override def sessionInboundObserved(count: Int): Boolean = ???
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/OutboundStreamStateImplSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/OutboundStreamStateImplSuite.scala
index 361c18453..e4d3528c9 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/OutboundStreamStateImplSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/OutboundStreamStateImplSuite.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.testkit.BlazeTestSuite
 import scala.concurrent.duration.Duration
 import scala.util.Failure
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class OutboundStreamStateImplSuite extends BlazeTestSuite {
 
   private class Ctx(connectionState: Connection.State) {
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/PingManagerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/PingManagerSuite.scala
index 7b32fb154..a96d58b20 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/PingManagerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/PingManagerSuite.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.util.BufferTools
 
 import scala.util.{Failure, Success}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class PingManagerSuite extends BlazeTestSuite {
   test("A PingManager should write a ping") {
     val tools = new MockTools(isClient = false)
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrame.scala b/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrame.scala
index e63f78c02..67ce134e8 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrame.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrame.scala
@@ -19,8 +19,10 @@ package org.http4s.blaze.http.http2
 import org.http4s.blaze.http.http2.Http2Settings.Setting
 
 // TODO: these may form the basis of what gets written to the WriteListener
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 sealed abstract class ProtocolFrame private extends Product with Serializable
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 object ProtocolFrame {
   case class GoAway(lastHandleStream: Int, cause: Http2Exception) extends ProtocolFrame
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrameDecoder.scala b/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrameDecoder.scala
index e0d9ea1fd..6afff57a8 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrameDecoder.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/ProtocolFrameDecoder.scala
@@ -22,6 +22,7 @@ import java.nio.ByteBuffer
 import org.http4s.blaze.http.http2.Http2Settings.Setting
 import org.http4s.blaze.http.http2.mocks.MockFrameListener
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] object ProtocolFrameDecoder {
   private[this] class Listener(inHeaderSequence: Boolean)
       extends MockFrameListener(inHeaderSequence) {
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/ServerPriorKnowledgeHandshakerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/ServerPriorKnowledgeHandshakerSuite.scala
index 776a11b0d..846508358 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/ServerPriorKnowledgeHandshakerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/ServerPriorKnowledgeHandshakerSuite.scala
@@ -24,6 +24,7 @@ import org.http4s.blaze.util.BufferTools
 
 import scala.util.{Failure, Success}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class ServerPriorKnowledgeHandshakerSuite extends BlazeTestSuite {
   private def makeHandshaker(
       localSettings: ImmutableHttp2Settings
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/SessionFlowControlSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/SessionFlowControlSuite.scala
index 389dcfb94..ecc9852c9 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/SessionFlowControlSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/SessionFlowControlSuite.scala
@@ -20,6 +20,7 @@ import org.http4s.blaze.http.http2.Http2Settings.DefaultSettings
 import org.http4s.blaze.http.http2.mocks.MockTools
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class SessionFlowControlSuite extends BlazeTestSuite {
   private class TestSessionFlowControl(session: SessionCore)
       extends SessionFlowControlImpl(session, null) {
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/SessionFrameListenerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/SessionFrameListenerSuite.scala
index 10ce24893..580a91809 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/SessionFrameListenerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/SessionFrameListenerSuite.scala
@@ -28,6 +28,7 @@ import org.http4s.blaze.util.BufferTools
 
 import scala.util.Success
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class SessionFrameListenerSuite extends BlazeTestSuite {
   private class MockTools(isClient: Boolean) extends mocks.MockTools(isClient) {
     lazy val headerDecoder: HeaderDecoder =
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/StreamFlowWindowSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/StreamFlowWindowSuite.scala
index 407a0f352..97860423f 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/StreamFlowWindowSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/StreamFlowWindowSuite.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2
 import org.http4s.blaze.http.http2.mocks.{MockTools, ObservingSessionFlowControl}
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class StreamFlowWindowSuite extends BlazeTestSuite {
   private class Tools extends MockTools(isClient = true) {
     override lazy val sessionFlowControl: SessionFlowControl =
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/StreamIdManagerSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/StreamIdManagerSuite.scala
index 8cdefc5ed..35a913975 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/StreamIdManagerSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/StreamIdManagerSuite.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2
 
 import org.http4s.blaze.testkit.BlazeTestSuite
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class StreamIdManagerSuite extends BlazeTestSuite {
   private def newClientManager() = StreamIdManager(true)
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/StreamManagerImplSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/StreamManagerImplSuite.scala
index 8b8f00fce..edcbac2f5 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/StreamManagerImplSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/StreamManagerImplSuite.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.testkit.BlazeTestSuite
 
 import scala.util.Failure
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class StreamManagerImplSuite extends BlazeTestSuite {
   private class MockTools(isClient: Boolean) extends mocks.MockTools(isClient) {
     override lazy val streamManager: StreamManager =
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/StreamStateImplSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/StreamStateImplSuite.scala
index 3dd7a95c0..de41d5850 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/StreamStateImplSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/StreamStateImplSuite.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.util.BufferTools
 
 import scala.util.{Failure, Success}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class StreamStateImplSuite extends BlazeTestSuite {
   private class Ctx {
     val streamId = 1
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/WriteControllerImplSuite.scala b/http/src/test/scala/org/http4s/blaze/http/http2/WriteControllerImplSuite.scala
index cd58b1f1a..a18f8d0b7 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/WriteControllerImplSuite.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/WriteControllerImplSuite.scala
@@ -25,6 +25,7 @@ import org.http4s.blaze.testkit.BlazeTestSuite
 import scala.collection.mutable
 import scala.concurrent.{Future, Promise}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 class WriteControllerImplSuite extends BlazeTestSuite {
   private def mockData(i: Int): ByteBuffer =
     ByteBuffer.wrap {
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockByteBufferHeadStage.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockByteBufferHeadStage.scala
index fb133c781..5ef8e4f56 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockByteBufferHeadStage.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockByteBufferHeadStage.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2.mocks
 import java.nio.ByteBuffer
 import org.http4s.blaze.util.BufferTools
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockByteBufferHeadStage extends MockHeadStage[ByteBuffer] {
   override def name: String = "Head"
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockFrameListener.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockFrameListener.scala
index 0dc247a46..60a03f2c2 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockFrameListener.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockFrameListener.scala
@@ -21,6 +21,7 @@ import java.nio.ByteBuffer
 import org.http4s.blaze.http.http2.Http2Settings.Setting
 import org.http4s.blaze.http.http2.{FrameListener, Priority, Result}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockFrameListener(inHeaders: Boolean) extends FrameListener {
   override def inHeaderSequence: Boolean = inHeaders
   override def onGoAwayFrame(lastStream: Int, errorCode: Long, debugData: Array[Byte]): Result = ???
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeadStage.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeadStage.scala
index 2c377231d..6b4639bcd 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeadStage.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeadStage.scala
@@ -20,6 +20,7 @@ import org.http4s.blaze.pipeline.HeadStage
 import scala.collection.mutable
 import scala.concurrent.{Future, Promise}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockHeadStage[T] extends HeadStage[T] {
   override def name: String = "Head"
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeaderAggregatingFrameListener.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeaderAggregatingFrameListener.scala
index 340725208..65944bec5 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeaderAggregatingFrameListener.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockHeaderAggregatingFrameListener.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.http._
 import org.http4s.blaze.http.http2.Http2Settings.Setting
 import org.http4s.blaze.http.http2._
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockHeaderAggregatingFrameListener
     extends HeaderAggregatingFrameListener(
       Http2Settings.default,
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamFlowWindow.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamFlowWindow.scala
index aec274b63..64432eec8 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamFlowWindow.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamFlowWindow.scala
@@ -18,6 +18,7 @@ package org.http4s.blaze.http.http2.mocks
 
 import org.http4s.blaze.http.http2.{Http2Exception, SessionFlowControl, StreamFlowWindow}
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockStreamFlowWindow extends StreamFlowWindow {
   override def sessionFlowControl: SessionFlowControl = ???
   override def streamUnconsumedBytes: Int = ???
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamManager.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamManager.scala
index e0b388a5e..e9794e717 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamManager.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockStreamManager.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.http.http2.{MaybeError, Result, _}
 import scala.collection.mutable
 import scala.concurrent.Future
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockStreamManager() extends StreamManager {
   override def size: Int = 0
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockTools.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockTools.scala
index 5c62c68a5..8168f8627 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockTools.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockTools.scala
@@ -22,6 +22,7 @@ import org.http4s.blaze.util.Execution
 import scala.concurrent.ExecutionContext
 import scala.concurrent.duration.Duration
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockTools(isClient: Boolean) extends SessionCore {
   def flowStrategy: FlowStrategy = new DefaultFlowStrategy(localSettings)
 
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockWriteController.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockWriteController.scala
index 3166cef0a..affaee924 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockWriteController.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/MockWriteController.scala
@@ -25,6 +25,7 @@ import scala.collection.mutable
 import scala.collection.mutable.ListBuffer
 import scala.concurrent.Future
 
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class MockWriteController extends WriteController {
   var closeCalled = false
   val observedInterests = new ListBuffer[WriteInterest]
diff --git a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/ObservingSessionFlowControl.scala b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/ObservingSessionFlowControl.scala
index 363ee4fa7..026f2033f 100644
--- a/http/src/test/scala/org/http4s/blaze/http/http2/mocks/ObservingSessionFlowControl.scala
+++ b/http/src/test/scala/org/http4s/blaze/http/http2/mocks/ObservingSessionFlowControl.scala
@@ -19,6 +19,7 @@ package org.http4s.blaze.http.http2.mocks
 import org.http4s.blaze.http.http2.{SessionCore, SessionFlowControlImpl, StreamFlowWindow}
 
 /** Extends the [[SessionFlowControlImpl]] class but makes a couple critical methods no-ops */
+@deprecated("HTTP/2 support is unmaintained and will be removed in a future version.", "0.23.18")
 private[http2] class ObservingSessionFlowControl(
     session: SessionCore
 ) extends SessionFlowControlImpl(
diff --git a/nix/nixpkgs-version.json b/nix/nixpkgs-version.json
deleted file mode 100644
index 200fa61a3..000000000
--- a/nix/nixpkgs-version.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-    "owner": "nixos",
-    "repo": "nixpkgs",
-    "rev": "61290574123116a36225811f3ea6a7cfdf0fd17b",
-    "sha256": "1vwcjnx3nf9cw7xvi92lrd46k7sycvq9m1dfgq2myw02z5zklv06",
-    "fetchSubmodules": true
-}
\ No newline at end of file
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 0e64fe15c..000000000
--- a/shell.nix
+++ /dev/null
@@ -1,11 +0,0 @@
-let
-  java = "openjdk8_headless";
-  pkgs = import ./nix/pkgs.nix { inherit java; };
-in
-pkgs.mkShell {
-  buildInputs = [
-    pkgs.git
-    pkgs.${java}
-    pkgs.sbt
-  ];
-}