diff --git a/libs/input/android/os/IInputConstants.aidl b/libs/input/android/os/IInputConstants.aidl
index 82c220f..6316b59 100644
--- a/libs/input/android/os/IInputConstants.aidl
+++ b/libs/input/android/os/IInputConstants.aidl
@@ -21,4 +21,11 @@
 interface IInputConstants
 {
     const int DEFAULT_DISPATCHING_TIMEOUT_MILLIS = 5000; // 5 seconds
+
+    // Compatibility changes.
+    /**
+      * TODO(b/157929241): remove this before closing the bug. This is needed temporarily
+      * to identify apps that are using this flag.
+      */
+    const long BLOCK_FLAG_SLIPPERY = 157929241;
 }