diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index cea5bad..027418a 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -37,6 +37,10 @@
         enabled: true,
     },
     double_loadable: true,
+
+    // libbinder does not offer a stable wire protocol.
+    // if a second copy of it is installed, then it may break after security
+    // or dessert updates. Instead, apex users should use libbinder_ndk.
     no_apex: true,
 
     srcs: [