diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 4fa7b445..49241ef1 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -2,7 +2,7 @@ name: build
 on:
   pull_request:
   push:
-    branches: [ rolling ]
+    branches: [ humble ]
   workflow_dispatch:
   schedule:
     # Run every morning to detect flakiness and broken dependencies
@@ -17,17 +17,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          # Rolling (source)
-          - ROS_DISTRO: rolling
-            BUILD_TYPE: source
-          # Jazzy (binary)
-          - ROS_DISTRO: jazzy
+          # Humble (binary)
+          - ROS_DISTRO: humble
             BUILD_TYPE: binary
     env:
       ROS2_REPOS_FILE_URL: 'https://raw.githubusercontent.com/ros2/ros2/${{ matrix.ROS_DISTRO }}/ros2.repos'
     runs-on: ubuntu-latest
     container:
-      image: ${{ matrix.BUILD_TYPE == 'binary' && format('ros:{0}-ros-base', matrix.ROS_DISTRO) || 'ubuntu:noble' }}
+      image: ${{ matrix.BUILD_TYPE == 'binary' && format('ros:{0}-ros-base', matrix.ROS_DISTRO) || 'ubuntu:jammy' }}
     steps:
     - uses: ros-tooling/setup-ros@v0.7
       if: ${{ matrix.BUILD_TYPE == 'source' }}
diff --git a/.github/workflows/style.yaml b/.github/workflows/style.yaml
index 6389ca52..7bade92f 100644
--- a/.github/workflows/style.yaml
+++ b/.github/workflows/style.yaml
@@ -2,7 +2,7 @@ name: style
 on:
   pull_request:
   push:
-    branches: [ rolling ]
+    branches: [ humble ]
 defaults:
   run:
     shell: bash
@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        distro: ['jazzy', 'rolling']
+        distro: ['humble']
     container:
       image: ros:${{ matrix.distro }}-ros-base
     timeout-minutes: 30
diff --git a/README.md b/README.md
index 9e56025a..d67a5c31 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # rmw_zenoh
 
-[![build](https://github.com/ros2/rmw_zenoh/actions/workflows/build.yaml/badge.svg)](https://github.com/ros2/rmw_zenoh/actions/workflows/build.yaml)
-[![style](https://github.com/ros2/rmw_zenoh/actions/workflows/style.yaml/badge.svg)](https://github.com/ros2/rmw_zenoh/actions/workflows/style.yaml)
+[![build](https://github.com/ros2/rmw_zenoh/actions/workflows/build.yaml/badge.svg?branch=humble)](https://github.com/ros2/rmw_zenoh/actions/workflows/build.yaml)
+[![style](https://github.com/ros2/rmw_zenoh/actions/workflows/style.yaml/badge.svg?branch=humble)](https://github.com/ros2/rmw_zenoh/actions/workflows/style.yaml)
 
 A ROS 2 RMW implementation based on Zenoh that is written using the zenoh-cpp bindings.
 
@@ -10,8 +10,9 @@ A ROS 2 RMW implementation based on Zenoh that is written using the zenoh-cpp bi
 For information about the Design please visit [design](docs/design.md) page.
 
 ## Requirements
-- [ROS 2](https://docs.ros.org): Rolling/Jazzy/Iron
+- [ROS 2](https://docs.ros.org)
 
+> Note: See available distro branches, eg. `jazzy`, for supported ROS 2 distributions.
 
 ## Setup
 
@@ -22,11 +23,12 @@ The `ZENOHC_CARGO_FLAGS` CMake argument may be overwritten with other features i
 See [zenoh_cpp_vendor/CMakeLists.txt](./zenoh_cpp_vendor/CMakeLists.txt) for more details.
 
 ```bash
+# replace <DISTRO> with ROS 2 distro of choice
 mkdir ~/ws_rmw_zenoh/src -p && cd ~/ws_rmw_zenoh/src
-git clone https://github.com/ros2/rmw_zenoh.git
+git clone https://github.com/ros2/rmw_zenoh.git -b <DISTRO>
 cd ~/ws_rmw_zenoh
-rosdep install --from-paths src --ignore-src --rosdistro <DISTRO> -y # replace <DISTRO> with ROS 2 distro of choice
-source /opt/ros/<DISTRO>/setup.bash # replace <DISTRO> with ROS 2 distro of choice
+rosdep install --from-paths src --ignore-src --rosdistro <DISTRO> -y
+source /opt/ros/<DISTRO>/setup.bash
 colcon build --cmake-args -DCMAKE_BUILD_TYPE=Release
 ```
 
diff --git a/rmw_zenoh_cpp/CMakeLists.txt b/rmw_zenoh_cpp/CMakeLists.txt
index 185fa804..d7ee3721 100644
--- a/rmw_zenoh_cpp/CMakeLists.txt
+++ b/rmw_zenoh_cpp/CMakeLists.txt
@@ -94,7 +94,7 @@ if(BUILD_TESTING)
 
   set(_linter_excludes src/detail/ordered_hash.hpp src/detail/ordered_map.hpp)
 
-  ament_copyright(EXCLUDE src/detail/simplified_xxhash3.cpp src/detail/simplified_xxhash3.hpp)
+  ament_copyright(EXCLUDE src/detail/simplified_xxhash3.cpp src/detail/simplified_xxhash3.hpp ${_linter_excludes})
   ament_cpplint(EXCLUDE ${_linter_excludes})
   ament_lint_cmake()
   ament_uncrustify(EXCLUDE ${_linter_excludes})
diff --git a/rmw_zenoh_cpp/src/detail/attachment_helpers.cpp b/rmw_zenoh_cpp/src/detail/attachment_helpers.cpp
index 6f128b47..9a10fc5e 100644
--- a/rmw_zenoh_cpp/src/detail/attachment_helpers.cpp
+++ b/rmw_zenoh_cpp/src/detail/attachment_helpers.cpp
@@ -32,7 +32,7 @@ namespace rmw_zenoh_cpp
 AttachmentData::AttachmentData(
   const int64_t sequence_number,
   const int64_t source_timestamp,
-  const std::array<uint8_t, RMW_GID_STORAGE_SIZE> source_gid)
+  const std::array<uint8_t, 16> source_gid)
 : sequence_number_(sequence_number),
   source_timestamp_(source_timestamp),
   source_gid_(source_gid),
@@ -61,7 +61,7 @@ int64_t AttachmentData::source_timestamp() const
 }
 
 ///=============================================================================
-std::array<uint8_t, RMW_GID_STORAGE_SIZE> AttachmentData::copy_gid() const
+std::array<uint8_t, 16> AttachmentData::copy_gid() const
 {
   return source_gid_;
 }
@@ -103,7 +103,7 @@ AttachmentData::AttachmentData(const zenoh::Bytes & bytes)
   if (source_gid_str != "source_gid") {
     throw std::runtime_error("source_gid is not found in the attachment.");
   }
-  this->source_gid_ = deserializer.deserialize<std::array<uint8_t, RMW_GID_STORAGE_SIZE>>();
+  this->source_gid_ = deserializer.deserialize<std::array<uint8_t, 16>>();
   gid_hash_ = hash_gid(this->source_gid_);
 }
 }  // namespace rmw_zenoh_cpp
diff --git a/rmw_zenoh_cpp/src/detail/attachment_helpers.hpp b/rmw_zenoh_cpp/src/detail/attachment_helpers.hpp
index 64f444d1..6de90587 100644
--- a/rmw_zenoh_cpp/src/detail/attachment_helpers.hpp
+++ b/rmw_zenoh_cpp/src/detail/attachment_helpers.hpp
@@ -31,14 +31,14 @@ class AttachmentData final
   AttachmentData(
     const int64_t sequence_number,
     const int64_t source_timestamp,
-    const std::array<uint8_t, RMW_GID_STORAGE_SIZE> source_gid);
+    const std::array<uint8_t, 16> source_gid);
 
   explicit AttachmentData(const zenoh::Bytes & bytes);
   explicit AttachmentData(AttachmentData && data);
 
   int64_t sequence_number() const;
   int64_t source_timestamp() const;
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> copy_gid() const;
+  std::array<uint8_t, 16> copy_gid() const;
   size_t gid_hash() const;
 
   zenoh::Bytes serialize_to_zbytes();
@@ -46,7 +46,7 @@ class AttachmentData final
 private:
   int64_t sequence_number_;
   int64_t source_timestamp_;
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> source_gid_;
+  std::array<uint8_t, 16> source_gid_;
   size_t gid_hash_;
 };
 }  // namespace rmw_zenoh_cpp
diff --git a/rmw_zenoh_cpp/src/detail/event.cpp b/rmw_zenoh_cpp/src/detail/event.cpp
index dff88118..c54692d3 100644
--- a/rmw_zenoh_cpp/src/detail/event.cpp
+++ b/rmw_zenoh_cpp/src/detail/event.cpp
@@ -33,11 +33,6 @@ static const std::unordered_map<rmw_event_type_t, rmw_zenoh_cpp::rmw_zenoh_event
   {RMW_EVENT_REQUESTED_QOS_INCOMPATIBLE, rmw_zenoh_cpp::ZENOH_EVENT_REQUESTED_QOS_INCOMPATIBLE},
   {RMW_EVENT_OFFERED_QOS_INCOMPATIBLE, rmw_zenoh_cpp::ZENOH_EVENT_OFFERED_QOS_INCOMPATIBLE},
   {RMW_EVENT_MESSAGE_LOST, rmw_zenoh_cpp::ZENOH_EVENT_MESSAGE_LOST},
-  {RMW_EVENT_SUBSCRIPTION_MATCHED, rmw_zenoh_cpp::ZENOH_EVENT_SUBSCRIPTION_MATCHED},
-  {RMW_EVENT_PUBLICATION_MATCHED, rmw_zenoh_cpp::ZENOH_EVENT_PUBLICATION_MATCHED},
-  {RMW_EVENT_SUBSCRIPTION_INCOMPATIBLE_TYPE,
-    rmw_zenoh_cpp::ZENOH_EVENT_SUBSCRIPTION_INCOMPATIBLE_TYPE},
-  {RMW_EVENT_PUBLISHER_INCOMPATIBLE_TYPE, rmw_zenoh_cpp::ZENOH_EVENT_PUBLISHER_INCOMPATIBLE_TYPE}
   // TODO(clalancette): Implement remaining events
 };
 }  // namespace
diff --git a/rmw_zenoh_cpp/src/detail/graph_cache.cpp b/rmw_zenoh_cpp/src/detail/graph_cache.cpp
index 6b2f9388..af5b67d5 100644
--- a/rmw_zenoh_cpp/src/detail/graph_cache.cpp
+++ b/rmw_zenoh_cpp/src/detail/graph_cache.cpp
@@ -33,8 +33,6 @@
 #include "rmw/validate_namespace.h"
 #include "rmw/validate_node_name.h"
 
-#include "rosidl_runtime_c/type_hash.h"
-
 #include "graph_cache.hpp"
 #include "logging_macros.hpp"
 
@@ -233,7 +231,8 @@ void GraphCache::handle_matched_events_for_put(
       }
       // Update event counters for the new entity.
       if (is_entity_local(*entity) && match_count_for_entity > 0) {
-        update_event_counters(entity,
+        update_event_counters(
+          entity,
           ZENOH_EVENT_PUBLICATION_MATCHED,
           match_count_for_entity);
       }
@@ -1124,18 +1123,7 @@ rmw_ret_t GraphCache::get_entities_info_by_topic(
           return ret;
         }
 
-        rosidl_type_hash_t type_hash;
-        rcutils_ret_t rc_ret = rosidl_parse_type_hash_string(
-          topic_data->info_.type_hash_.c_str(),
-          &type_hash);
-        if (RCUTILS_RET_OK == rc_ret) {
-          ret = rmw_topic_endpoint_info_set_topic_type_hash(&ep, &type_hash);
-          if (RMW_RET_OK != ret) {
-            return ret;
-          }
-        }
-
-        memcpy(ep.endpoint_gid, entity->copy_gid().data(), RMW_GID_STORAGE_SIZE);
+        memcpy(ep.endpoint_gid, entity->copy_gid().data(), 16);
 
         endpoints.push_back(ep);
       }
diff --git a/rmw_zenoh_cpp/src/detail/liveliness_utils.cpp b/rmw_zenoh_cpp/src/detail/liveliness_utils.cpp
index c1792091..cab43512 100644
--- a/rmw_zenoh_cpp/src/detail/liveliness_utils.cpp
+++ b/rmw_zenoh_cpp/src/detail/liveliness_utils.cpp
@@ -179,8 +179,6 @@ static const std::unordered_map<std::string, rmw_qos_liveliness_policy_e> str_to
   {std::to_string(RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC),
     RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC},
   {std::to_string(RMW_QOS_POLICY_LIVELINESS_UNKNOWN), RMW_QOS_POLICY_LIVELINESS_UNKNOWN},
-  {std::to_string(RMW_QOS_POLICY_LIVELINESS_BEST_AVAILABLE),
-    RMW_QOS_POLICY_LIVELINESS_BEST_AVAILABLE}
 };
 
 std::vector<std::string> split_keyexpr(
@@ -438,8 +436,9 @@ Entity::Entity(
   simplified_XXH128_hash_t keyexpr_gid =
     simplified_XXH3_128bits(this->liveliness_keyexpr_.c_str(), this->liveliness_keyexpr_.length());
   memcpy(this->gid_.data(), &keyexpr_gid.low64, sizeof(keyexpr_gid.low64));
-  memcpy(this->gid_.data() + sizeof(keyexpr_gid.low64), &keyexpr_gid.high64,
-        sizeof(keyexpr_gid.high64));
+  memcpy(
+    this->gid_.data() + sizeof(keyexpr_gid.low64), &keyexpr_gid.high64,
+    sizeof(keyexpr_gid.high64));
 
   // We also hash the liveliness keyexpression into a size_t that we use to index into our maps.
   this->keyexpr_hash_ = hash_gid(this->gid_);
@@ -631,7 +630,7 @@ std::string Entity::liveliness_keyexpr() const
 }
 
 ///=============================================================================
-std::array<uint8_t, RMW_GID_STORAGE_SIZE> Entity::copy_gid() const
+std::array<uint8_t, 16> Entity::copy_gid() const
 {
   return gid_;
 }
@@ -672,7 +671,7 @@ std::string demangle_name(const std::string & input)
 }  // namespace liveliness
 
 ///=============================================================================
-size_t hash_gid(const std::array<uint8_t, RMW_GID_STORAGE_SIZE> gid)
+size_t hash_gid(const std::array<uint8_t, 16> gid)
 {
   std::stringstream hash_str;
   hash_str << std::hex;
diff --git a/rmw_zenoh_cpp/src/detail/liveliness_utils.hpp b/rmw_zenoh_cpp/src/detail/liveliness_utils.hpp
index 81880df6..ca7dc6d6 100644
--- a/rmw_zenoh_cpp/src/detail/liveliness_utils.hpp
+++ b/rmw_zenoh_cpp/src/detail/liveliness_utils.hpp
@@ -173,7 +173,7 @@ class Entity
   // Two entities are equal if their keyexpr_hash are equal.
   bool operator==(const Entity & other) const;
 
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> copy_gid() const;
+  std::array<uint8_t, 16> copy_gid() const;
 
 private:
   Entity(
@@ -192,7 +192,7 @@ class Entity
   NodeInfo node_info_;
   std::optional<TopicInfo> topic_info_;
   std::string liveliness_keyexpr_;
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> gid_{};
+  std::array<uint8_t, 16> gid_{};
 };
 
 ///=============================================================================
@@ -235,7 +235,7 @@ std::optional<rmw_qos_profile_t> keyexpr_to_qos(const std::string & keyexpr);
 }  // namespace liveliness
 
 ///=============================================================================
-size_t hash_gid(const std::array<uint8_t, RMW_GID_STORAGE_SIZE> gid);
+size_t hash_gid(const std::array<uint8_t, 16> gid);
 }  // namespace rmw_zenoh_cpp
 
 ///=============================================================================
diff --git a/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
index a0463945..497ca869 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
@@ -66,9 +66,6 @@ std::shared_ptr<ClientData> ClientData::make(
     return nullptr;
   }
 
-  rcutils_allocator_t * allocator = &node->context->options.allocator;
-
-  const rosidl_type_hash_t * type_hash = type_support->get_type_hash_func(type_support);
   auto service_members = static_cast<const service_type_support_callbacks_t *>(type_support->data);
   auto request_members = static_cast<const message_type_support_callbacks_t *>(
     service_members->request_members_->data);
@@ -92,20 +89,9 @@ std::shared_ptr<ClientData> ClientData::make(
     return nullptr;
   }
 
-  // Convert the type hash to a string so that it can be included in the keyexpr.
-  char * type_hash_c_str = nullptr;
-  rcutils_ret_t stringify_ret = rosidl_stringify_type_hash(
-    type_hash,
-    *allocator,
-    &type_hash_c_str);
-  if (RCUTILS_RET_BAD_ALLOC == stringify_ret) {
-    // rosidl_stringify_type_hash already set the error
-    return nullptr;
-  }
-  auto free_type_hash_c_str = rcpputils::make_scope_exit(
-    [&allocator, &type_hash_c_str]() {
-      allocator->deallocate(type_hash_c_str, allocator->state);
-    });
+  // Humble doesn't support type hash, but we leave it in place as a constant so we don't have to
+  // change the graph and liveliness token code.
+  const char * type_hash_c_str = "TypeHashNotSupported";
 
   std::size_t domain_id = node_info.domain_id_;
   auto entity = liveliness::Entity::make(
@@ -203,7 +189,7 @@ bool ClientData::liveliness_is_valid() const
 }
 
 ///=============================================================================
-std::array<uint8_t, RMW_GID_STORAGE_SIZE> ClientData::copy_gid() const
+std::array<uint8_t, 16> ClientData::copy_gid() const
 {
   return entity_->copy_gid();
 }
@@ -307,7 +293,7 @@ rmw_ret_t ClientData::take_response(
   memcpy(
     request_header->request_id.writer_guid,
     attachment.copy_gid().data(),
-    RMW_GID_STORAGE_SIZE);
+    16);
   request_header->received_timestamp = latest_reply->get_received_timestamp();
 
   *taken = true;
@@ -364,7 +350,7 @@ rmw_ret_t ClientData::send_request(
 
   // Send request
   zenoh::Session::GetOptions opts = zenoh::Session::GetOptions::create_default();
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> local_gid = entity_->copy_gid();
+  std::array<uint8_t, 16> local_gid = entity_->copy_gid();
   opts.attachment = rmw_zenoh_cpp::create_map_and_set_sequence_num(*sequence_id, local_gid);
   opts.target = Z_QUERY_TARGET_ALL_COMPLETE;
   // The default timeout for a z_get query is 10 seconds and if a response is not received within
diff --git a/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
index 44b187ba..1bb52992 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
@@ -65,7 +65,7 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
   bool liveliness_is_valid() const;
 
   // Copy the GID of this ClientData into an rmw_gid_t.
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> copy_gid() const;
+  std::array<uint8_t, 16> copy_gid() const;
 
   // Add a new ZenohReply to the queue.
   void add_new_reply(std::unique_ptr<rmw_zenoh_cpp::ZenohReply> reply);
diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
index 3bf62372..3a4be059 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
@@ -60,27 +60,12 @@ std::shared_ptr<PublisherData> PublisherData::make(
     return nullptr;
   }
 
-  rcutils_allocator_t * allocator = &node->context->options.allocator;
-
-  const rosidl_type_hash_t * type_hash = type_support->get_type_hash_func(type_support);
   auto callbacks = static_cast<const message_type_support_callbacks_t *>(type_support->data);
   auto message_type_support = std::make_unique<MessageTypeSupport>(callbacks);
 
-  // Convert the type hash to a string so that it can be included in
-  // the keyexpr.
-  char * type_hash_c_str = nullptr;
-  rcutils_ret_t stringify_ret = rosidl_stringify_type_hash(
-    type_hash,
-    *allocator,
-    &type_hash_c_str);
-  if (RCUTILS_RET_BAD_ALLOC == stringify_ret) {
-    // rosidl_stringify_type_hash already set the error
-    return nullptr;
-  }
-  auto always_free_type_hash_c_str = rcpputils::make_scope_exit(
-    [&allocator, &type_hash_c_str]() {
-      allocator->deallocate(type_hash_c_str, allocator->state);
-    });
+  // Humble doesn't support type hash, but we leave it in place as a constant so we don't have to
+  // change the graph and liveliness token code.
+  const char * type_hash_c_str = "TypeHashNotSupported";
 
   std::size_t domain_id = node_info.domain_id_;
   auto entity = liveliness::Entity::make(
@@ -328,7 +313,7 @@ liveliness::TopicInfo PublisherData::topic_info() const
   return entity_->topic_info().value();
 }
 
-std::array<uint8_t, RMW_GID_STORAGE_SIZE> PublisherData::copy_gid() const
+std::array<uint8_t, 16> PublisherData::copy_gid() const
 {
   std::lock_guard<std::mutex> lock(mutex_);
   return entity_->copy_gid();
diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
index 52c22523..b7658adf 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
@@ -70,7 +70,7 @@ class PublisherData final
   liveliness::TopicInfo topic_info() const;
 
   // Return a copy of the GID of this publisher.
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> copy_gid() const;
+  std::array<uint8_t, 16> copy_gid() const;
 
   // Returns true if liveliness token is still valid.
   bool liveliness_is_valid() const;
diff --git a/rmw_zenoh_cpp/src/detail/rmw_service_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_service_data.cpp
index f3df2df6..4b43bf39 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_service_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_service_data.cpp
@@ -62,9 +62,6 @@ std::shared_ptr<ServiceData> ServiceData::make(
     return nullptr;
   }
 
-  rcutils_allocator_t * allocator = &node->context->options.allocator;
-
-  const rosidl_type_hash_t * type_hash = type_support->get_type_hash_func(type_support);
   auto service_members = static_cast<const service_type_support_callbacks_t *>(type_support->data);
   auto request_members = static_cast<const message_type_support_callbacks_t *>(
     service_members->request_members_->data);
@@ -88,20 +85,9 @@ std::shared_ptr<ServiceData> ServiceData::make(
     return nullptr;
   }
 
-  // Convert the type hash to a string so that it can be included in the keyexpr.
-  char * type_hash_c_str = nullptr;
-  rcutils_ret_t stringify_ret = rosidl_stringify_type_hash(
-    type_hash,
-    *allocator,
-    &type_hash_c_str);
-  if (RCUTILS_RET_BAD_ALLOC == stringify_ret) {
-    // rosidl_stringify_type_hash already set the error
-    return nullptr;
-  }
-  auto free_type_hash_c_str = rcpputils::make_scope_exit(
-    [&allocator, &type_hash_c_str]() {
-      allocator->deallocate(type_hash_c_str, allocator->state);
-    });
+  // Humble doesn't support type hash, but we leave it in place as a constant so we don't have to
+  // change the graph and liveliness token code.
+  const char * type_hash_c_str = "TypeHashNotSupported";
 
   std::size_t domain_id = node_info.domain_id_;
   auto entity = liveliness::Entity::make(
@@ -329,8 +315,8 @@ rmw_ret_t ServiceData::take_request(
     return RMW_RET_ERROR;
   }
 
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> writer_guid = attachment.copy_gid();
-  memcpy(request_header->request_id.writer_guid, writer_guid.data(), RMW_GID_STORAGE_SIZE);
+  std::array<uint8_t, 16> writer_guid = attachment.copy_gid();
+  memcpy(request_header->request_id.writer_guid, writer_guid.data(), 16);
 
   request_header->source_timestamp = attachment.source_timestamp();
   if (request_header->source_timestamp < 0) {
@@ -374,8 +360,8 @@ rmw_ret_t ServiceData::send_response(
     return RMW_RET_OK;
   }
 
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> writer_guid;
-  memcpy(writer_guid.data(), request_id->writer_guid, RMW_GID_STORAGE_SIZE);
+  std::array<uint8_t, 16> writer_guid;
+  memcpy(writer_guid.data(), request_id->writer_guid, 16);
 
   // Create the queryable payload
   const size_t hash = hash_gid(writer_guid);
@@ -433,8 +419,8 @@ rmw_ret_t ServiceData::send_response(
 
   const zenoh::Query & loaned_query = query->get_query();
   zenoh::Query::ReplyOptions options = zenoh::Query::ReplyOptions::create_default();
-  std::array<uint8_t, RMW_GID_STORAGE_SIZE> writer_gid;
-  memcpy(writer_gid.data(), request_id->writer_guid, RMW_GID_STORAGE_SIZE);
+  std::array<uint8_t, 16> writer_gid;
+  memcpy(writer_gid.data(), request_id->writer_guid, 16);
   options.attachment = create_map_and_set_sequence_num(
     request_id->sequence_number,
     writer_gid);
diff --git a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.cpp
index 2a070ee8..4950564e 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.cpp
@@ -73,26 +73,12 @@ std::shared_ptr<SubscriptionData> SubscriptionData::make(
     return nullptr;
   }
 
-  rcutils_allocator_t * allocator = &node->context->options.allocator;
-
-  const rosidl_type_hash_t * type_hash = type_support->get_type_hash_func(type_support);
   auto callbacks = static_cast<const message_type_support_callbacks_t *>(type_support->data);
   auto message_type_support = std::make_unique<MessageTypeSupport>(callbacks);
 
-  // Convert the type hash to a string so that it can be included in the keyexpr.
-  char * type_hash_c_str = nullptr;
-  rcutils_ret_t stringify_ret = rosidl_stringify_type_hash(
-    type_hash,
-    *allocator,
-    &type_hash_c_str);
-  if (RCUTILS_RET_BAD_ALLOC == stringify_ret) {
-    // rosidl_stringify_type_hash already set the error
-    return nullptr;
-  }
-  auto free_type_hash_c_str = rcpputils::make_scope_exit(
-    [&allocator, &type_hash_c_str]() {
-      allocator->deallocate(type_hash_c_str, allocator->state);
-    });
+  // Humble doesn't support type hash, but we leave it in place as a constant so we don't have to
+  // change the graph and liveliness token code.
+  const char * type_hash_c_str = "TypeHashNotSupported";
 
   // Everything above succeeded and is setup properly. Now declare a subscriber
   // with Zenoh; after this, callbacks may come in at any time.
@@ -520,7 +506,7 @@ rmw_ret_t SubscriptionData::take_one_message(
     memcpy(
       message_info->publisher_gid.data,
       msg_data->attachment.copy_gid().data(),
-      RMW_GID_STORAGE_SIZE);
+      16);
     message_info->from_intra_process = false;
   }
   *taken = true;
@@ -577,7 +563,7 @@ rmw_ret_t SubscriptionData::take_serialized_message(
     memcpy(
       message_info->publisher_gid.data,
       msg_data->attachment.copy_gid().data(),
-      RMW_GID_STORAGE_SIZE);
+      16);
     message_info->from_intra_process = false;
   }
 
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_utils.cpp b/rmw_zenoh_cpp/src/detail/zenoh_utils.cpp
index 922a80fb..d097b2e7 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_utils.cpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_utils.cpp
@@ -28,7 +28,7 @@ namespace rmw_zenoh_cpp
 {
 ///=============================================================================
 zenoh::Bytes create_map_and_set_sequence_num(
-  int64_t sequence_number, std::array<uint8_t, RMW_GID_STORAGE_SIZE> gid)
+  int64_t sequence_number, std::array<uint8_t, 16> gid)
 {
   auto now = std::chrono::system_clock::now().time_since_epoch();
   auto now_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(now);
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_utils.hpp b/rmw_zenoh_cpp/src/detail/zenoh_utils.hpp
index 58ed471d..c4f646aa 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_utils.hpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_utils.hpp
@@ -31,7 +31,7 @@ namespace rmw_zenoh_cpp
 {
 ///=============================================================================
 zenoh::Bytes create_map_and_set_sequence_num(
-  int64_t sequence_number, std::array<uint8_t, RMW_GID_STORAGE_SIZE> gid);
+  int64_t sequence_number, std::array<uint8_t, 16> gid);
 
 ///=============================================================================
 // A class to store the replies to service requests.
diff --git a/rmw_zenoh_cpp/src/rmw_event.cpp b/rmw_zenoh_cpp/src/rmw_event.cpp
index b362a042..6c4e83a3 100644
--- a/rmw_zenoh_cpp/src/rmw_event.cpp
+++ b/rmw_zenoh_cpp/src/rmw_event.cpp
@@ -227,26 +227,6 @@ rmw_take_event(
         *taken = true;
         return RMW_RET_OK;
       }
-    case rmw_zenoh_cpp::ZENOH_EVENT_SUBSCRIPTION_INCOMPATIBLE_TYPE:
-    case rmw_zenoh_cpp::ZENOH_EVENT_PUBLISHER_INCOMPATIBLE_TYPE: {
-        auto ei = static_cast<rmw_incompatible_type_status_t *>(event_info);
-        RMW_CHECK_ARGUMENT_FOR_NULL(ei, RMW_RET_INVALID_ARGUMENT);
-        ei->total_count = static_cast<int32_t>(st.total_count);
-        ei->total_count_change = static_cast<int32_t>(st.total_count_change);
-        *taken = true;
-        return RMW_RET_OK;
-      }
-    case rmw_zenoh_cpp::ZENOH_EVENT_PUBLICATION_MATCHED:
-    case rmw_zenoh_cpp::ZENOH_EVENT_SUBSCRIPTION_MATCHED: {
-        auto ei = static_cast<rmw_matched_status_t *>(event_info);
-        RMW_CHECK_ARGUMENT_FOR_NULL(ei, RMW_RET_INVALID_ARGUMENT);
-        ei->total_count = st.total_count;
-        ei->total_count_change = st.total_count_change;
-        ei->current_count = st.current_count;
-        ei->current_count_change = st.current_count_change;
-        *taken = true;
-        return RMW_RET_OK;
-      }
     case rmw_zenoh_cpp::ZENOH_EVENT_OFFERED_QOS_INCOMPATIBLE: {
         auto ei = static_cast<rmw_offered_qos_incompatible_event_status_t *>(event_info);
         RMW_CHECK_ARGUMENT_FOR_NULL(ei, RMW_RET_INVALID_ARGUMENT);
diff --git a/rmw_zenoh_cpp/src/rmw_init.cpp b/rmw_zenoh_cpp/src/rmw_init.cpp
index cb34697c..c983c0d6 100644
--- a/rmw_zenoh_cpp/src/rmw_init.cpp
+++ b/rmw_zenoh_cpp/src/rmw_init.cpp
@@ -84,9 +84,13 @@ rmw_init(const rmw_init_options_t * options, rmw_context_t * context)
       }
     });
 
-  if (!rcutils_set_env_overwrite(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_WARN_LEVEL_STR, 0)) {
-    RMW_SET_ERROR_MSG("Error configuring Zenoh logging.");
-    return RMW_RET_ERROR;
+  // Equivalent to rcutils_set_env_overwrite(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_WARN_LEVEL_STR, 0)
+  // in modern ROS 2.
+  if (getenv(ZENOH_LOG_ENV_VAR_STR) == nullptr) {
+    if (!rcutils_set_env(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_WARN_LEVEL_STR)) {
+      RMW_SET_ERROR_MSG("Error configuring Zenoh logging.");
+      return RMW_RET_ERROR;
+    }
   }
 
   // Enable the zenoh built-in logger
diff --git a/rmw_zenoh_cpp/src/rmw_init_options.cpp b/rmw_zenoh_cpp/src/rmw_init_options.cpp
index 15e06e2b..8ace30a5 100644
--- a/rmw_zenoh_cpp/src/rmw_init_options.cpp
+++ b/rmw_zenoh_cpp/src/rmw_init_options.cpp
@@ -47,8 +47,8 @@ rmw_init_options_init(rmw_init_options_t * init_options, rcutils_allocator_t all
   init_options->enclave = nullptr;
   init_options->domain_id = RMW_DEFAULT_DOMAIN_ID;
   init_options->security_options = rmw_get_default_security_options();
-  init_options->discovery_options = rmw_get_zero_initialized_discovery_options();
-  return rmw_discovery_options_init(&(init_options->discovery_options), 0, &allocator);
+  init_options->localhost_only = RMW_LOCALHOST_ONLY_DEFAULT;
+  return RMW_RET_OK;
 }
 
 //==============================================================================
@@ -87,19 +87,6 @@ rmw_init_options_copy(const rmw_init_options_t * src, rmw_init_options_t * dst)
     [&tmp, allocator]() {
       rmw_security_options_fini(&tmp.security_options, &allocator);
     });
-  tmp.discovery_options = rmw_get_zero_initialized_discovery_options();
-  ret = rmw_discovery_options_copy(
-    &src->discovery_options,
-    &allocator,
-    &tmp.discovery_options);
-  if (RMW_RET_OK != ret) {
-    return ret;
-  }
-  auto free_discovery_options = rcpputils::make_scope_exit(
-    [&tmp]() {
-      rmw_ret_t tmp_ret = rmw_discovery_options_fini(&tmp.discovery_options);
-      static_cast<void>(tmp_ret);
-    });
   tmp.enclave = nullptr;
   if (nullptr != src->enclave) {
     tmp.enclave = rcutils_strdup(src->enclave, allocator);
@@ -122,7 +109,6 @@ rmw_init_options_copy(const rmw_init_options_t * src, rmw_init_options_t * dst)
   *dst = tmp;
 
   free_enclave.cancel();
-  free_discovery_options.cancel();
   free_security_options.cancel();
 
   return RMW_RET_OK;
@@ -152,7 +138,6 @@ rmw_init_options_fini(rmw_init_options_t * init_options)
     return ret;
   }
 
-  ret = rmw_discovery_options_fini(&init_options->discovery_options);
   *init_options = rmw_get_zero_initialized_init_options();
 
   return ret;
diff --git a/rmw_zenoh_cpp/src/rmw_zenoh.cpp b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
index 23220fdf..ed1d06ef 100644
--- a/rmw_zenoh_cpp/src/rmw_zenoh.cpp
+++ b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
@@ -47,7 +47,6 @@
 #include "rcutils/types.h"
 
 #include "rmw/allocators.h"
-#include "rmw/dynamic_message_type_support.h"
 #include "rmw/error_handling.h"
 #include "rmw/features.h"
 #include "rmw/impl/cpp/macros.hpp"
@@ -139,10 +138,6 @@ bool rmw_feature_supported(rmw_feature_t feature)
       return false;
     case RMW_FEATURE_MESSAGE_INFO_RECEPTION_SEQUENCE_NUMBER:
       return false;
-    case RMW_MIDDLEWARE_SUPPORTS_TYPE_DISCOVERY:
-      return true;
-    case RMW_MIDDLEWARE_CAN_TAKE_DYNAMIC_MESSAGE:
-      return false;
     default:
       return false;
   }
@@ -497,51 +492,6 @@ rmw_destroy_publisher(rmw_node_t * node, rmw_publisher_t * publisher)
   return RMW_RET_OK;
 }
 
-//==============================================================================
-rmw_ret_t
-rmw_take_dynamic_message(
-  const rmw_subscription_t * subscription,
-  rosidl_dynamic_typesupport_dynamic_data_t * dynamic_message,
-  bool * taken,
-  rmw_subscription_allocation_t * allocation)
-{
-  static_cast<void>(subscription);
-  static_cast<void>(dynamic_message);
-  static_cast<void>(taken);
-  static_cast<void>(allocation);
-  return RMW_RET_UNSUPPORTED;
-}
-
-//==============================================================================
-rmw_ret_t
-rmw_take_dynamic_message_with_info(
-  const rmw_subscription_t * subscription,
-  rosidl_dynamic_typesupport_dynamic_data_t * dynamic_message,
-  bool * taken,
-  rmw_message_info_t * message_info,
-  rmw_subscription_allocation_t * allocation)
-{
-  static_cast<void>(subscription);
-  static_cast<void>(dynamic_message);
-  static_cast<void>(taken);
-  static_cast<void>(message_info);
-  static_cast<void>(allocation);
-  return RMW_RET_UNSUPPORTED;
-}
-
-//==============================================================================
-rmw_ret_t
-rmw_serialization_support_init(
-  const char * serialization_lib_name,
-  rcutils_allocator_t * allocator,
-  rosidl_dynamic_typesupport_serialization_support_t * serialization_support)
-{
-  static_cast<void>(serialization_lib_name);
-  static_cast<void>(allocator);
-  static_cast<void>(serialization_support);
-  return RMW_RET_UNSUPPORTED;
-}
-
 //==============================================================================
 /// Borrow a loaned ROS message.
 rmw_ret_t
@@ -2451,7 +2401,7 @@ rmw_get_gid_for_publisher(const rmw_publisher_t * publisher, rmw_gid_t * gid)
   RMW_CHECK_ARGUMENT_FOR_NULL(pub_data, RMW_RET_INVALID_ARGUMENT);
 
   gid->implementation_identifier = rmw_zenoh_cpp::rmw_zenoh_identifier;
-  memcpy(gid->data, pub_data->copy_gid().data(), RMW_GID_STORAGE_SIZE);
+  memcpy(gid->data, pub_data->copy_gid().data(), 16);
 
   return RMW_RET_OK;
 }
@@ -2468,7 +2418,7 @@ rmw_get_gid_for_client(const rmw_client_t * client, rmw_gid_t * gid)
   RMW_CHECK_ARGUMENT_FOR_NULL(client_data, RMW_RET_INVALID_ARGUMENT);
 
   gid->implementation_identifier = rmw_zenoh_cpp::rmw_zenoh_identifier;
-  memcpy(gid->data, client_data->copy_gid().data(), RMW_GID_STORAGE_SIZE);
+  memcpy(gid->data, client_data->copy_gid().data(), 16);
 
   return RMW_RET_OK;
 }
@@ -2492,7 +2442,7 @@ rmw_compare_gids_equal(const rmw_gid_t * gid1, const rmw_gid_t * gid2, bool * re
     return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
   RMW_CHECK_ARGUMENT_FOR_NULL(result, RMW_RET_INVALID_ARGUMENT);
 
-  *result = memcmp(gid1->data, gid2->data, RMW_GID_STORAGE_SIZE) == 0;
+  *result = memcmp(gid1->data, gid2->data, 16) == 0;
 
   return RMW_RET_OK;
 }
diff --git a/rmw_zenoh_cpp/src/zenohd/main.cpp b/rmw_zenoh_cpp/src/zenohd/main.cpp
index bbba50f1..a1e8c3bf 100644
--- a/rmw_zenoh_cpp/src/zenohd/main.cpp
+++ b/rmw_zenoh_cpp/src/zenohd/main.cpp
@@ -57,9 +57,13 @@ int main(int argc, char ** argv)
   (void)argc;
   (void)argv;
 
-  if (!rcutils_set_env_overwrite(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_INFO_LEVEL_STR, 0)) {
-    RMW_SET_ERROR_MSG("Error configuring Zenoh logging.");
-    return 1;
+  // Equivalent to rcutils_set_env_overwrite(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_WARN_LEVEL_STR, 0)
+  // in modern ROS 2.
+  if (getenv(ZENOH_LOG_ENV_VAR_STR) == nullptr) {
+    if (!rcutils_set_env(ZENOH_LOG_ENV_VAR_STR, ZENOH_LOG_WARN_LEVEL_STR)) {
+      RMW_SET_ERROR_MSG("Error configuring Zenoh logging.");
+      return RMW_RET_ERROR;
+    }
   }
 
   // Enable the zenoh built-in logger