doc: migration: 4.2: Add information about net_mgmt API changes

Add information how the net_mgmt request handler is changed.
The event number type is changed from uint32_t to uint64_t to allow
the event command to be a bit mask instead of enum value.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>

doc/releases/migration-guide-4.2.rst

@@ -482,6 +482,21 @@ Networking
   need to update their response callback implementations. To retain current
   behavior, simply return 0 from the callback.
 
+* The API signature of ``net_mgmt`` event handler :c:type:`net_mgmt_event_handler_t` and
+  request handler :c:type:`net_mgmt_request_handler_t` has changed. The management event
+  type is changed from ``uint32_t`` to ``uint64_t``. The change allows event number values
+  to be bit masks instead of enum values. The layer code still stays as a enum value.
+  The :c:macro:`NET_MGMT_LAYER_CODE` and :c:macro:`NET_MGMT_GET_COMMAND` can be used to get
+  the layer code and management event command from the actual event value in the request or
+  event handlers if needed.
+
+* The socket options for ``net_mgmt`` type sockets cannot directly be network management
+  event types as those are now ``uint64_t`` and the socket option expects a normal 32 bit
+  integer value. Because of this, a new ``SO_NET_MGMT_ETHERNET_SET_QAV_PARAM``
+  and ``SO_NET_MGMT_ETHERNET_GET_QAV_PARAM`` socket options are created that will replace
+  the previously used ``NET_REQUEST_ETHERNET_GET_QAV_PARAM`` and
+  ``NET_REQUEST_ETHERNET_GET_QAV_PARAM`` options.
+
 OpenThread
 ==========
 

doc/releases/release-notes-4.2.rst

@@ -111,6 +111,13 @@ Deprecated APIs and options
   was deprecated since Zephyr 4.0, and users were advised to migrate to alternative
   crypto backends.
 
+Stable API changes in this release
+==================================
+
+* The API signature of ``net_mgmt`` event handler :c:type:`net_mgmt_event_handler_t`
+  and request handler :c:type:`net_mgmt_request_handler_t` has changed. The event value
+  type is changed from ``uint32_t`` to ``uint64_t``.
+
 New APIs and options
 ====================