diff --git a/compatibility_matrices/compatibility_matrix.current.xml b/compatibility_matrices/compatibility_matrix.current.xml
index 002ff31..464b4a3 100644
--- a/compatibility_matrices/compatibility_matrix.current.xml
+++ b/compatibility_matrices/compatibility_matrix.current.xml
@@ -178,9 +178,11 @@
     <hal format="hidl" optional="false">
         <name>android.hardware.keymaster</name>
         <version>3.0</version>
+        <version>4.0</version>
         <interface>
             <name>IKeymasterDevice</name>
             <instance>default</instance>
+	    <!-- TODO: strongbox here? -->
         </interface>
     </hal>
     <hal format="hidl" optional="true">