diff --git a/compatibility_matrices/compatibility_matrix.3.xml b/compatibility_matrices/compatibility_matrix.3.xml
index a75ed25..468735d 100644
--- a/compatibility_matrices/compatibility_matrix.3.xml
+++ b/compatibility_matrices/compatibility_matrix.3.xml
@@ -207,7 +207,10 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl" optional="false">
+    <!-- Either the AIDL or the HIDL health HAL must exist on the device.
+         If the HIDL health HAL exists, it must be at least version 2.0.
+         See DeviceManifestTest.HealthHal -->
+    <hal format="hidl" optional="true">
         <name>android.hardware.health</name>
         <version>2.0</version>
         <interface>
diff --git a/compatibility_matrices/compatibility_matrix.4.xml b/compatibility_matrices/compatibility_matrix.4.xml
index 3b8ee21..96f291f 100644
--- a/compatibility_matrices/compatibility_matrix.4.xml
+++ b/compatibility_matrices/compatibility_matrix.4.xml
@@ -213,7 +213,10 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl" optional="false">
+    <!-- Either the AIDL or the HIDL health HAL must exist on the device.
+         If the HIDL health HAL exists, it must be at least version 2.0.
+         See DeviceManifestTest.HealthHal -->
+    <hal format="hidl" optional="true">
         <name>android.hardware.health</name>
         <version>2.0</version>
         <interface>
diff --git a/compatibility_matrices/compatibility_matrix.5.xml b/compatibility_matrices/compatibility_matrix.5.xml
index 0fb21a7..3642814 100644
--- a/compatibility_matrices/compatibility_matrix.5.xml
+++ b/compatibility_matrices/compatibility_matrix.5.xml
@@ -238,7 +238,10 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl" optional="false">
+    <!-- Either the AIDL or the HIDL health HAL must exist on the device.
+         If the HIDL health HAL exists, it must be at least version 2.1.
+         See DeviceManifestTest.HealthHal -->
+    <hal format="hidl" optional="true">
         <name>android.hardware.health</name>
         <version>2.1</version>
         <interface>
diff --git a/compatibility_matrices/compatibility_matrix.6.xml b/compatibility_matrices/compatibility_matrix.6.xml
index aee2c51..9c42cb0 100644
--- a/compatibility_matrices/compatibility_matrix.6.xml
+++ b/compatibility_matrices/compatibility_matrix.6.xml
@@ -268,7 +268,10 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl" optional="false">
+    <!-- Either the AIDL or the HIDL health HAL must exist on the device.
+         If the HIDL health HAL exists, it must be at least version 2.1.
+         See DeviceManifestTest.HealthHal -->
+    <hal format="hidl" optional="true">
         <name>android.hardware.health</name>
         <version>2.1</version>
         <interface>