Update the release notes for ecFlow 5.12.4 release

docs/release_notes/version_5.12.rst

@@ -9,13 +9,19 @@ Version 5.12 updates
 Version 5.12.4
 ==============
 
-* `Released <https://confluence.ecmwf.int/display/ECFLOW/Releases>`__\  on 2024-03-XX
+* `Released <https://confluence.ecmwf.int/display/ECFLOW/Releases>`__\  on 2024-03-23
 
 ecFlow Client
 -------------
 
 - **Bug** corrected ecFlow Python3 module linkage (specific for conda-forge) :jiraissue:`ECFLOW-1950`
 
+ecFlow HTTP
+-----------
+
+- **Feature** added :code:`id` field to each Node in the :code:`/<path>/tree` endpoint response :jiraissue:`ECFLOW-1952`
+- **Improvement** added *flag* attribute to Nodes in the :code:`/<path>/tree` endpoint response :jiraissue:`ECFLOW-1954`
+- **Bug** corrected Alias node structure in the :code:`/<path>/tree` endpoint response :jiraissue:`ECFLOW-1953`
 
 Version 5.12.3
 ==============