diff --git a/microdroid/payload/metadata.proto b/microdroid/payload/metadata.proto
index 9e60b38..2e92f55 100644
--- a/microdroid/payload/metadata.proto
+++ b/microdroid/payload/metadata.proto
@@ -43,6 +43,10 @@
   // The timestamp in seconds when the APEX was last updated. This should match the value in
   // apex-info-list.xml.
   uint64 last_update_seconds = 5;
+
+  // Required.
+  // Whether the APEX is a factory version or not.
+  bool is_factory = 6;
 }
 
 message ApkPayload {
diff --git a/microdroid_manager/src/instance.rs b/microdroid_manager/src/instance.rs
index 1068792..5a77198 100644
--- a/microdroid_manager/src/instance.rs
+++ b/microdroid_manager/src/instance.rs
@@ -336,4 +336,5 @@
     pub public_key: Vec<u8>,
     pub root_digest: Vec<u8>,
     pub last_update_seconds: u64,
+    pub is_factory: bool,
 }
diff --git a/microdroid_manager/src/payload.rs b/microdroid_manager/src/payload.rs
index 661af5f..48535f3 100644
--- a/microdroid_manager/src/payload.rs
+++ b/microdroid_manager/src/payload.rs
@@ -48,6 +48,7 @@
                 public_key: result.public_key,
                 root_digest: result.root_digest,
                 last_update_seconds: apex.last_update_seconds,
+                is_factory: apex.is_factory,
             })
         })
         .collect()
@@ -63,6 +64,7 @@
                 public_key: data.public_key.clone(),
                 root_digest: data.root_digest.clone(),
                 last_update_seconds: data.last_update_seconds,
+                is_factory: data.is_factory,
                 ..Default::default()
             })
             .collect(),
diff --git a/virtualizationservice/src/payload.rs b/virtualizationservice/src/payload.rs
index 65adc25..e4a763c 100644
--- a/virtualizationservice/src/payload.rs
+++ b/virtualizationservice/src/payload.rs
@@ -66,6 +66,9 @@
     // The field claims to be milliseconds but is actually seconds.
     #[serde(rename = "lastUpdateMillis")]
     last_update_seconds: u64,
+
+    #[serde(rename = "isFactory")]
+    is_factory: bool,
 }
 
 impl ApexInfoList {
@@ -137,6 +140,8 @@
                         let metadata = metadata(&apex_info.path)?;
                         apex_info.last_update_seconds =
                             metadata.modified()?.duration_since(SystemTime::UNIX_EPOCH)?.as_secs();
+                        // by definition, staged apex can't be a factory apex.
+                        apex_info.is_factory = false;
                     }
                 }
             }
@@ -158,10 +163,12 @@
             .iter()
             .enumerate()
             .map(|(i, apex_name)| {
+                let apex_info = apex_list.get(apex_name)?;
                 Ok(ApexPayload {
                     name: apex_name.clone(),
                     partition_name: format!("microdroid-apex-{}", i),
-                    last_update_seconds: apex_list.get(apex_name)?.last_update_seconds,
+                    last_update_seconds: apex_info.last_update_seconds,
+                    is_factory: apex_info.is_factory,
                     ..Default::default()
                 })
             })
@@ -411,12 +418,14 @@
                     path: PathBuf::from("path0"),
                     has_classpath_jar: false,
                     last_update_seconds: 12345678,
+                    is_factory: true,
                 },
                 ApexInfo {
                     name: "has_classpath".to_string(),
                     path: PathBuf::from("path1"),
                     has_classpath_jar: true,
                     last_update_seconds: 87654321,
+                    is_factory: false,
                 },
             ],
         };