diff --git a/bin/varnishd/cache/cache_backend.c b/bin/varnishd/cache/cache_backend.c
index fe7e4f4e1ce..3b168d76a3c 100644
--- a/bin/varnishd/cache/cache_backend.c
+++ b/bin/varnishd/cache/cache_backend.c
@@ -139,16 +139,8 @@ VBE_Connect_Error(struct VSC_vbe *vsc, int err)
 
 /*--------------------------------------------------------------------*/
 
-int
-VBE_is_ah_auto(const struct backend *bp)
-{
-
-	CHECK_OBJ_NOTNULL(bp, BACKEND_MAGIC);
-	return (bp->director->vdir->admin_health == VDI_AH_AUTO);
-}
-
-void
-VBE_connwait_signal_all(const struct backend *bp)
+static void
+vbe_connwait_signal_all(const struct backend *bp)
 {
 	struct connwait *cw;
 
@@ -661,6 +653,21 @@ vbe_healthy(VRT_CTX, VCL_BACKEND d, VCL_TIME *t)
 	return (!bp->sick);
 }
 
+static VCL_VOID v_matchproto_(vdi_notify_f)
+vbe_notify(VCL_BACKEND d)
+{
+	const struct vdi_ahealth *ah;
+	struct backend *bp;
+
+	CHECK_OBJ_NOTNULL(d, DIRECTOR_MAGIC);
+	CAST_OBJ_NOTNULL(bp, d->priv, BACKEND_MAGIC);
+	CHECK_OBJ_NOTNULL(d->vdir, VCLDIR_MAGIC);
+	ah = d->vdir->admin_health;
+
+	// sick == 0 for _noprobe
+	if (ah == VDI_AH_SICK || (ah == VDI_AH_AUTO && bp->sick))
+		vbe_connwait_signal_all(bp);
+}
 
 /*--------------------------------------------------------------------
  */
@@ -676,7 +683,8 @@ static const struct vdi_methods vbe_methods[1] = {{
 	.destroy =		vbe_destroy,
 	.panic =		vbe_panic,
 	.list =			vbe_list,
-	.healthy =		vbe_healthy
+	.healthy =		vbe_healthy,
+	.notify =		vbe_notify
 }};
 
 static const struct vdi_methods vbe_methods_noprobe[1] = {{
@@ -689,7 +697,8 @@ static const struct vdi_methods vbe_methods_noprobe[1] = {{
 	.event =		vbe_dir_event,
 	.destroy =		vbe_destroy,
 	.panic =		vbe_panic,
-	.list =			vbe_list
+	.list =			vbe_list,
+	.notify =		vbe_notify
 }};
 
 /*--------------------------------------------------------------------
diff --git a/bin/varnishd/cache/cache_backend_probe.c b/bin/varnishd/cache/cache_backend_probe.c
index 3b4fa2fa821..3941785f7de 100644
--- a/bin/varnishd/cache/cache_backend_probe.c
+++ b/bin/varnishd/cache/cache_backend_probe.c
@@ -191,10 +191,8 @@ VBP_Update_Backend(struct vbp_target *vt)
 	i = (vt->good < vt->threshold);
 	chg = (i != vt->backend->sick);
 	vt->backend->sick = i;
-	if (i && chg && (vt->backend->director != NULL &&
-	    VBE_is_ah_auto(vt->backend))) {
-		VBE_connwait_signal_all(vt->backend);
-	}
+	if (i && chg && vt->backend->director != NULL)
+		VRT_Notify(vt->backend->director);
 
 	AN(vt->backend->vcl_name);
 	VSL(SLT_Backend_health, NO_VXID,
diff --git a/bin/varnishd/cache/cache_director.c b/bin/varnishd/cache/cache_director.c
index 042ad9f345e..f15b5acd450 100644
--- a/bin/varnishd/cache/cache_director.c
+++ b/bin/varnishd/cache/cache_director.c
@@ -265,6 +265,22 @@ VRT_SetChanged(VCL_BACKEND d, VCL_TIME changed)
 		d->vdir->health_changed = changed;
 }
 
+/*--------------------------------------------------------------------
+ * Notify of change (admin_health for now) outside backend
+ */
+
+VCL_VOID
+VRT_Notify(VCL_BACKEND d)
+{
+
+	CHECK_OBJ_NOTNULL(d, DIRECTOR_MAGIC);
+	CHECK_OBJ_NOTNULL(d->vdir, VCLDIR_MAGIC);
+	CHECK_OBJ_NOTNULL(d->vdir->methods, VDI_METHODS_MAGIC);
+	if (d->vdir->methods->notify == NULL)
+		return;
+	d->vdir->methods->notify(d);
+}
+
 /* Send Event ----------------------------------------------------------
  */
 
@@ -477,7 +493,6 @@ static int v_matchproto_(vcl_be_func)
 do_set_health(struct cli *cli, struct director *d, void *priv)
 {
 	struct set_health *sh;
-	struct vrt_ctx *ctx;
 
 	(void)cli;
 	CHECK_OBJ_NOTNULL(d, DIRECTOR_MAGIC);
@@ -488,12 +503,7 @@ do_set_health(struct cli *cli, struct director *d, void *priv)
 	if (d->vdir->admin_health != sh->ah) {
 		d->vdir->health_changed = VTIM_real();
 		d->vdir->admin_health = sh->ah;
-		ctx = VCL_Get_CliCtx(0);
-		if (sh->ah == VDI_AH_SICK || (sh->ah == VDI_AH_AUTO &&
-		    d->vdir->methods->healthy != NULL &&
-		    !d->vdir->methods->healthy(ctx, d, NULL))) {
-			VBE_connwait_signal_all(d->priv);
-		    }
+		VRT_Notify(d);
 	}
 	return (0);
 }
diff --git a/bin/varnishd/cache/cache_varnishd.h b/bin/varnishd/cache/cache_varnishd.h
index e0b88b4aae9..e84f90e0f0e 100644
--- a/bin/varnishd/cache/cache_varnishd.h
+++ b/bin/varnishd/cache/cache_varnishd.h
@@ -161,11 +161,7 @@ void VCA_Init(void);
 void VCA_Shutdown(void);
 
 /* cache_backend.c */
-struct backend;
-
 void VBE_InitCfg(void);
-void VBE_connwait_signal_all(const struct backend *bp);
-int VBE_is_ah_auto(const struct backend *bp);
 
 /* cache_ban.c */
 
diff --git a/include/vrt.h b/include/vrt.h
index 144a7e2ed16..95928c2f38c 100644
--- a/include/vrt.h
+++ b/include/vrt.h
@@ -46,7 +46,7 @@
 #  error "include vdef.h before vrt.h"
 #endif
 
-#define VRT_MAJOR_VERSION	20U
+#define VRT_MAJOR_VERSION	21U
 
 #define VRT_MINOR_VERSION	0U
 
@@ -58,6 +58,9 @@
  * binary/load-time compatible, increment MAJOR version
  *
  * NEXT (2024-03-15)
+ * 21.0
+ *	notify callback added to struct vdi_methods
+ *	VRT_Notify() added
  * 20.0 (2024-09-13)
  *	struct vrt_backend.backend_wait_timeout added
  *	struct vrt_backend.backend_wait_limit  added
@@ -737,6 +740,7 @@ typedef void vdi_release_f(VCL_BACKEND);
 typedef void vdi_destroy_f(VCL_BACKEND);
 typedef void vdi_panic_f(VCL_BACKEND, struct vsb *);
 typedef void vdi_list_f(VRT_CTX, VCL_BACKEND, struct vsb *, int, int);
+typedef void vdi_notify_f(VCL_BACKEND);
 
 struct vdi_methods {
 	unsigned			magic;
@@ -755,6 +759,9 @@ struct vdi_methods {
 	vdi_destroy_f			*destroy;
 	vdi_panic_f			*panic;
 	vdi_list_f			*list;
+	// when something changes outside the backend's control
+	// (for now, admin health)
+	vdi_notify_f			*notify;
 };
 
 struct director {
@@ -767,6 +774,7 @@ struct director {
 };
 
 VCL_BOOL VRT_Healthy(VRT_CTX, VCL_BACKEND, VCL_TIME *);
+VCL_VOID VRT_Notify(VCL_BACKEND);
 VCL_VOID VRT_SetChanged(VCL_BACKEND, VCL_TIME);
 VCL_BACKEND VRT_AddDirector(VRT_CTX, const struct vdi_methods *,
     void *, const char *, ...) v_printflike_(4, 5);