ipfw: add UPDATING note and modify __FreeBSD_version

UPDATING

@@ -27,6 +27,13 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 15.x IS SLOW:
 	world, or to merely disable the most expensive debugging functionality
 	at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20250303:
+	Commit 4a77657cbc01 changed the ABI between ipfw(8) and ipfw(4).
+	Please note that the old ipfw(8) binary will not work with the new
+	ipfw(4) module. Therefore, it is recommended to disable ipfw during
+	the upgrade, otherwise the host system may become inaccessible because
+	ipfw rules cannot be installed with the old binary.
+
 20250214:
 	Commit 4517fbfd4251 modified the internal API between the
 	nfscommon and nfscl modules.  As such, both of these modules

sys/sys/param.h

@@ -73,7 +73,7 @@
  * cannot include sys/param.h and should only be updated here.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1500033
+#define __FreeBSD_version 1500034
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,