Update HIP-1137 based on implementation fedback

* Modified the NodeUpdateTransactionBody to use a wrapper message for the associated registered nodes.
   * This enables differentiating an empty list from an _unset_ list.
* Clarified that `RegisteredNodeDelete` will fail if that `RegisteredNode` is present in the
  `associated_registered_nodes` list for any Consensus `Node`.
* Added support for a `GeneralServiceEndpoint` endpoint type in `RegisteredServiceEndpoint` so
  that node operators can declare additional services for their nodes.

Signed-off-by: Joseph S. <121976561+jsync-swirlds@users.noreply.github.com>

Author: jsync-swirlds

HIP/hip-1137.md

@@ -14,7 +14,7 @@ discussions-to: https://github.com/hiero-ledger/hiero-improvement-proposals/pull
 status: Approved
 last-call-date-time: 2026-02-11T07:00:00Z
 created: 2025-03-07
-updated: 2026-02-10
+updated: 2026-03-05
 ---
 
 ## Abstract
@@ -233,6 +233,14 @@ message RegisteredServiceEndpoint {
          * Hiero consensus network.
          */
         RpcRelayEndpoint rpc_relay = 7;
+
+        /**
+         * A general service.<br/>
+         * A general service endpoint represents any network accessible service
+         * that is provided by a registered node but that is not a service
+         * currently defined as part of the Hiero Ledger system.
+         */
+        GeneralServiceEndpoint general_service = 8;
     }
 
     /**
@@ -296,6 +304,19 @@ message RegisteredServiceEndpoint {
      */
     message RpcRelayEndpoint {
     }
+
+    /**
+     * A message indicating this endpoint is a General Service endpoint.
+     */
+    message GeneralServiceEndpoint {
+        /**
+         * A short description of the service provided.
+         * <p>
+         * This value, if set, MUST NOT exceed 100 bytes when encoded as UTF-8.<br/>
+         * This field is OPTIONAL.
+         */
+        string description = 1;
+    }
 }
 ```
 
@@ -365,6 +386,10 @@ Service. This API function is used by the node operator to delete a node.
 This API function MAY also be used by an Hiero network's governance
 structure to administratively delete a registered node when necessary.
 
+If a `RegisteredNode` is present in the `associated_registered_nodes` list for
+any consensus `Node`, then that `RegisteredNode` cannot be deleted until it
+is first removed from the `associated_registered_nodes` list.
+
 ```protobuf
 message RegisteredNodeDeleteTransactionBody {
     /**
@@ -440,7 +465,7 @@ message RegisteredNodeUpdateTransactionBody {
      * If set, this list MUST NOT contain more than `50` entries.<br/>
      * If set, this list SHALL _replace_ the previous list.
      */
-    repeated com.hedera.hapi.node.addressbook.RegisteredServiceEndpoint service_endpoint = 4;
+    repeated RegisteredServiceEndpoint service_endpoint = 4;
 
     /**
      * An account identifier.<br/>
@@ -667,15 +692,32 @@ message NodeUpdateTransactionBody {
      * HIP-1137) that are operated by the same entity that operates this
      * consensus node.
      * <p>
-     * This field is OPTIONAL and MAY be empty.<br/>
-     * If set, this field SHALL overwrite any existing value.<br/>
+     * This field is OPTIONAL.<br/>
+     * If this field is not set, the current list SHALL NOT change.<br/>
+     * If this field is set, but contains an empty list, any existing
+     * associated registered nodes SHALL be removed.<br/>
      * This field MUST NOT contain more than twenty(20) entries.<br/>
      * Every entry in this list MUST be a valid `registered_node_id` for a
      * current registered node.
      */
-    repeated uint64 associated_registered_node = 11;
+    AssociatedRegisteredNodeList associated_registered_node_list = 11;
 }
 
+/**
+ * A wrapper around a list of associated registered node identifiers.<br/>
+ * This wrapper exists to enable an update transaction to differentiate
+ * between a field that is not set and an empty list of values.
+ * <p>
+ * An _unset_ field of this type SHALL NOT modify existing values.<br/>
+ * A _set_ field of this type with an empty list SHALL remove any
+ * existing values.
+ */
+message AssociatedRegisteredNodeList {
+    /**
+     * A list of registered node identifiers.
+     */
+    repeated uint64 associated_registered_node = 1;
+}
 ```
 
 ### Mirror node update
@@ -728,8 +770,6 @@ current proposal.
       1. The modification of registered nodes and consensus nodes have
          vastly different risk profiles, and mandate very different signatory
          requirements.
-
-## Open Issues
 1. Should we use a full Entity ID (0.0.1234 form) for registered node ID
    values, or is it reasonable to keep just a single integer (e.g. 28 or 18273)
    as the registered node ID.
@@ -745,6 +785,9 @@ current proposal.
      be integrated with community sentiment remains an open question.
    * This concept should be the subject of a future HIP.
 
+## Open Issues
+None
+
 ## Copyright/license
 <!-- SPDX-License-Identifier: Apache-2.0 -->
 This document is licensed under the Apache License, Version 2.0 --