diff --git a/src/render.c b/src/render.c
index c6acf584..b4fa7330 100644
--- a/src/render.c
+++ b/src/render.c
@@ -1136,7 +1136,13 @@ bool init_render(session_t *ps) {
 	}
 
 	// Blur filter
-	if (ps->o.blur_method) {
+	if (ps->o.blur_method && ps->o.blur_method != BLUR_METHOD_KERNEL) {
+		log_warn("Old backends only support blur method \"kernel\". Your blur "
+		         "setting will not be applied");
+		ps->o.blur_method = BLUR_METHOD_NONE;
+	}
+
+	if (ps->o.blur_method == BLUR_METHOD_KERNEL) {
 		ps->blur_kerns_cache =
 		    ccalloc(ps->o.blur_kernel_count, struct x_convolution_kernel *);