doc: update ChangeLog with release news

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/ChangeLog.md

@@ -4,9 +4,19 @@ Change Log
 All notable changes to the project are documented in this file.
 
 
-[v24.09.0][UNRELEASED]
+[v24.09.0][] - 2024-09-27
 -------------------------
 
+**News:** this release enhances the integration of all types of static
+routes with FRRouting ([Frr][]), including all routes that can be set by
+DHCP and IPvLL (ZeroConf) clients.  Due to this fundamental change, the
+system routing table is now primarily read from Frr, which increases the
+amount of relevant routing information available to the user.  E.g., in
+the CLI exec command `show ip route` and `show ipv6 route`.  Support for
+adjusting the administrative distance of all types of static routes has
+also been added to facilitate site specific adaptations.  Please see the
+documentation for details.
+
 ### Changes
 - Upgrade Buildroot to 2024.02.6 (LTS)
 - Upgrade Linux kernel to 6.6.52 (LTS)
@@ -65,6 +75,8 @@ All notable changes to the project are documented in this file.
   is now 1 minute, just like operations via other front-ends (NETCONF
   and RESTCONF). This was previously (incorrectly) set to 10 seconds.
 
+[Frr]: https://frrouting.org/
+
 
 [v24.08.0][] - 2024-08-30
 -------------------------