diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2cb0d78ce26..3775f2f8b41 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [7.0.18]
+
+[7.0.18]: https://github.com/microsoft/CCF/releases/tag/ccf-7.0.18
+
+### Removed
+
+- Nodes no longer accept forwarded RPC requests and responses in the legacy v1 and v2 wire formats. All supported releases have emitted the v3 format since 4.0, so mixed-version networks are unaffected (#8426).
+
 ## [7.0.17]
 
 [7.0.17]: https://github.com/microsoft/CCF/releases/tag/ccf-7.0.17
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 31ebba671f9..9c5b2e3da28 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ccf"
-version = "7.0.17"
+version = "7.0.18"
 authors = [
   { name="CCF Team", email="CCF-Sec@microsoft.com" },
 ]
diff --git a/src/node/node_types.h b/src/node/node_types.h
index 7f8c713f3a7..207c63488fd 100644
--- a/src/node/node_types.h
+++ b/src/node/node_types.h
@@ -38,11 +38,13 @@ namespace ccf
   // Types of frontend messages
   enum ForwardedMsg : Node2NodeMsg
   {
+    // No longer accepted on receive: all supported peers emit at least v3.
     forwarded_cmd_v1 = 0,
     forwarded_response_v1,
 
     // Includes a command_id, so that forwarded requests and responses can be
-    // precisely correlated. Supported since 2.0.8, emitted since 3.0.0
+    // precisely correlated. Supported since 2.0.8, emitted since 3.0.0.
+    // No longer accepted on receive: all supported peers emit at least v3.
     forwarded_cmd_v2,
     forwarded_response_v2,
 
diff --git a/src/node/rpc/forwarder.h b/src/node/rpc/forwarder.h
index 69f27675c21..f1072459996 100644
--- a/src/node/rpc/forwarder.h
+++ b/src/node/rpc/forwarder.h
@@ -299,65 +299,6 @@ namespace ccf
 
         switch (forwarded_msg)
         {
-          case ForwardedMsg::forwarded_cmd_v1:
-          {
-            auto ctx =
-              recv_forwarded_command<ForwardedHeader_v1>(from, data, size);
-
-            auto fwd_handler = get_forwarder_handler(ctx);
-            if (fwd_handler == nullptr)
-            {
-              return;
-            }
-
-            // frame_format is deliberately unset, the forwarder ignores it
-            // and expects the same format they forwarded.
-            ForwardedHeader_v1 response_header{
-              ForwardedMsg::forwarded_response_v1};
-
-            LOG_DEBUG_FMT("Sending forwarded response to {}", from);
-            fwd_handler->process_forwarded(ctx);
-
-            send_forwarded_response(
-              ctx->get_session_context()->client_session_id,
-              from,
-              response_header,
-              ctx->serialise_response());
-            break;
-          }
-
-          case ForwardedMsg::forwarded_cmd_v2:
-          {
-            auto ctx =
-              recv_forwarded_command<ForwardedHeader_v2>(from, data, size);
-
-            auto fwd_handler = get_forwarder_handler(ctx);
-            if (fwd_handler == nullptr)
-            {
-              return;
-            }
-
-            const auto forwarded_hdr_v2 =
-              serialized::peek<ForwardedHeader_v2>(data, size);
-            const auto cmd_id = forwarded_hdr_v2.id;
-
-            fwd_handler->process_forwarded(ctx);
-
-            // frame_format is deliberately unset, the forwarder ignores it
-            // and expects the same format they forwarded.
-            ForwardedHeader_v2 response_header{
-              {ForwardedMsg::forwarded_response_v2, {}}, cmd_id};
-
-            LOG_DEBUG_FMT("Sending forwarded response to {}", from);
-
-            send_forwarded_response(
-              ctx->get_session_context()->client_session_id,
-              from,
-              response_header,
-              ctx->serialise_response());
-            break;
-          }
-
           case ForwardedMsg::forwarded_cmd_v3:
           {
             auto ctx = recv_forwarded_command<ForwardedCommandHeader_v3>(
@@ -391,7 +332,6 @@ namespace ccf
           }
 
           case ForwardedMsg::forwarded_response_v3:
-          case ForwardedMsg::forwarded_response_v2:
           {
             const auto forwarded_hdr_v2 =
               serialized::peek<ForwardedHeader_v2>(data, size);
@@ -414,27 +354,9 @@ namespace ccf
                 cmd_id);
               return;
             }
-            // Deliberate fall-through
-          }
 
-          case ForwardedMsg::forwarded_response_v1:
-          {
-            std::optional<ForwardedResponseResult> rep;
-            if (forwarded_msg == ForwardedMsg::forwarded_response_v3)
-            {
-              rep = recv_forwarded_response<ForwardedResponseHeader_v3>(
-                from, data, size);
-            }
-            else if (forwarded_msg == ForwardedMsg::forwarded_response_v2)
-            {
-              rep =
-                recv_forwarded_response<ForwardedHeader_v2>(from, data, size);
-            }
-            else
-            {
-              rep =
-                recv_forwarded_response<ForwardedHeader_v1>(from, data, size);
-            }
+            auto rep = recv_forwarded_response<ForwardedResponseHeader_v3>(
+              from, data, size);
 
             if (!rep.has_value())
             {
@@ -459,6 +381,18 @@ namespace ccf
             break;
           }
 
+          case ForwardedMsg::forwarded_cmd_v1:
+          case ForwardedMsg::forwarded_response_v1:
+          case ForwardedMsg::forwarded_cmd_v2:
+          case ForwardedMsg::forwarded_response_v2:
+          {
+            LOG_FAIL_FMT(
+              "Forwarded msg type {} is no longer supported on receive, "
+              "dropping message",
+              (size_t)forwarded_msg);
+            break;
+          }
+
           default:
           {
             LOG_FAIL_FMT("Unknown frontend msg type: {}", forwarded_msg);