diff --git a/android/app/src/main/java/com/anonymous/bulwarkmobile/sync/PushRouting.kt b/android/app/src/main/java/com/anonymous/bulwarkmobile/sync/PushRouting.kt
index 3bdcca1b..70c0b97d 100644
--- a/android/app/src/main/java/com/anonymous/bulwarkmobile/sync/PushRouting.kt
+++ b/android/app/src/main/java/com/anonymous/bulwarkmobile/sync/PushRouting.kt
@@ -13,7 +13,7 @@ import org.json.JSONObject
  * The relay forwards the JMAP StateChange's `changed` map verbatim (FCM data
  * key `changed`: JMAP account id → type → state; only its first account is
  * repeated as `accountId`), so every account key is looked at. The mail task
- * runs only for mail: when some account's map has `EmailDelivery`, for an
+ * runs only for mail: when some account's map has a mail type, for an
  * EmailPush, or when `changed` is missing or unreadable (older relays), so a
  * contact change never ends in a mail notification.
  */
@@ -28,7 +28,15 @@ object PushRouting {
     )
 
     private const val EMAIL_PUSH_KIND = "jmap-email-push"
-    private const val EMAIL_DELIVERY = "EmailDelivery"
+
+    /**
+     * Types that may mean new mail: `EmailDelivery`, and `Email`/`Mailbox`,
+     * which new mail changes too. A subscription made by an older build
+     * listens to them until the launch-time resync replaces its types, and a
+     * server without `EmailDelivery` has only them. Keep in sync with
+     * MAIL_TYPES in src/lib/push-background-task.ts.
+     */
+    private val MAIL_TYPES = setOf("EmailDelivery", "Email", "Mailbox")
     private val CONTACT_TYPES = setOf("ContactCard", "AddressBook")
     private val CALENDAR_TYPES = setOf("CalendarEvent", "Calendar")
 
@@ -42,7 +50,7 @@ object PushRouting {
                 mail = true
                 continue
             }
-            if (EMAIL_DELIVERY in types) mail = true
+            if (types.any { it in MAIL_TYPES }) mail = true
             val contacts = types.any { it in CONTACT_TYPES }
             val calendar = types.any { it in CALENDAR_TYPES }
             for (route in routes[jmapAccountId].orEmpty()) {
diff --git a/android/app/src/test/java/com/anonymous/bulwarkmobile/sync/PushRoutingTest.kt b/android/app/src/test/java/com/anonymous/bulwarkmobile/sync/PushRoutingTest.kt
index 1a13656d..8e608022 100644
--- a/android/app/src/test/java/com/anonymous/bulwarkmobile/sync/PushRoutingTest.kt
+++ b/android/app/src/test/java/com/anonymous/bulwarkmobile/sync/PushRoutingTest.kt
@@ -64,6 +64,26 @@ class PushRoutingTest {
         assertEquals(setOf("alice-work" to calendar), decision.syncs)
     }
 
+    @Test
+    fun `an Email or Mailbox change is possible mail, as a subscription from an older build sends it`() {
+        for (changed in listOf(
+            """{"c":{"Email":"s1","Mailbox":"s2"}}""",
+            """{"c":{"Email":"s1"}}""",
+            """{"c":{"Mailbox":"s1"}}""",
+        )) {
+            val decision = PushRouting.decide(stateChange(changed), routes)
+            assertTrue("changed=$changed", decision.startMailTask)
+            assertTrue("changed=$changed", decision.syncs.isEmpty())
+        }
+        val mixed = PushRouting.decide(stateChange("""{"team":{"CalendarEvent":"e1"},"c":{"Email":"s1"}}"""), routes)
+        assertTrue(mixed.startMailTask)
+        assertEquals(setOf("alice-work" to calendar), mixed.syncs)
+        // Types that are neither mail nor device sync say nothing about mail.
+        val other = PushRouting.decide(stateChange("""{"c":{"Thread":"t1","ContactCard":"s1"}}"""), routes)
+        assertFalse(other.startMailTask)
+        assertEquals(setOf("alice@example.org" to contacts), other.syncs)
+    }
+
     @Test
     fun `an email push always starts the mail task`() {
         val data = mapOf("kind" to "jmap-email-push", "accountId" to "c", "changed" to """{"c":{"EmailDelivery":"s"}}""")
diff --git a/src/lib/__tests__/push-background-task.test.ts b/src/lib/__tests__/push-background-task.test.ts
index c8984ad9..8f1f0dae 100644
--- a/src/lib/__tests__/push-background-task.test.ts
+++ b/src/lib/__tests__/push-background-task.test.ts
@@ -237,6 +237,42 @@ describe('pushes for device sync (#34)', () => {
     await pushBackgroundTask(stateChange({ 'jmap-primary': { EmailDelivery: 'm1', ContactCard: 's1' } }));
     expect(jmapClient.getStoredCredentials).toHaveBeenCalledWith(LOCAL);
   });
+
+  it('takes an Email or Mailbox change for possible mail, as a subscription from an older build sends it', () => {
+    expect(carriesNoMail(parseRelayPushData(stateChange({ a: { Email: 's1', Mailbox: 's2' } })))).toBe(false);
+    expect(carriesNoMail(parseRelayPushData(stateChange({ a: { Email: 's1' } })))).toBe(false);
+    expect(carriesNoMail(parseRelayPushData(stateChange({ a: { Mailbox: 's1' } })))).toBe(false);
+    expect(carriesNoMail(parseRelayPushData(stateChange({ a: { CalendarEvent: 'e1' }, b: { Email: 's1' } })))).toBe(false);
+    // Types that are neither mail nor device sync say nothing about mail.
+    expect(carriesNoMail(parseRelayPushData(stateChange({ a: { Thread: 't1', ContactCard: 's1' } })))).toBe(true);
+  });
+
+  it('notifies new mail from a subscription that listens to Email and Mailbox', async () => {
+    (secureFetch as ReturnType<typeof vi.fn>).mockImplementation(async (url: string, init?: { body?: string }) => {
+      if (url.endsWith('/.well-known/jmap')) {
+        return {
+          ok: true,
+          json: async () => ({
+            apiUrl: 'https://mail.example.com/jmap/',
+            primaryAccounts: { 'urn:ietf:params:jmap:mail': 'jmap-primary' },
+            accounts: { 'jmap-primary': {} },
+          }),
+        };
+      }
+      // The legacy path: the inbox, its newest unread ids, then the messages.
+      const [[name]] = JSON.parse(init?.body ?? '{}').methodCalls;
+      const body = name === 'Mailbox/get'
+        ? { list: [{ id: 'inbox', role: 'inbox' }] }
+        : name === 'Email/query'
+          ? { ids: ['m1'] }
+          : { list: [{ id: 'm1', threadId: 't1', keywords: {}, subject: 'Hi', from: [{ email: 'bob@example.com' }] }] };
+      return { ok: true, json: async () => ({ methodResponses: [[name, body, '0']] }) };
+    });
+
+    await pushBackgroundTask(stateChange({ 'jmap-primary': { Email: 's1', Mailbox: 's2' } }));
+
+    expect(showNotification).toHaveBeenCalledWith(expect.objectContaining({ emailId: 'm1', accountId: LOCAL }));
+  });
 });
 
 describe('selectNotifiableEmails', () => {
diff --git a/src/lib/push-background-task.ts b/src/lib/push-background-task.ts
index 776b39c4..2c703f8e 100644
--- a/src/lib/push-background-task.ts
+++ b/src/lib/push-background-task.ts
@@ -378,18 +378,25 @@ async function detachedNewestUnreadInboxIds(
   return (qBody.ids as string[]) ?? [];
 }
 
+// Types that may mean new mail: `EmailDelivery`, and `Email`/`Mailbox`, which
+// new mail changes too. A subscription made by an older build listens to them
+// until the launch-time resync replaces its types, and a server without
+// `EmailDelivery` has only them. Keep in sync with MAIL_TYPES in PushRouting.kt.
+const MAIL_TYPES = ['EmailDelivery', 'Email', 'Mailbox'];
+
 /**
  * A StateChange push in which no account got new mail: only contact or
  * calendar changes, which the native push router already turned into device
- * syncs (#34, docs/device-sync.md "Triggers"). Without `EmailDelivery` there
- * is nothing to notify, and the legacy path (the newest unread mail) must
- * not run for it. An empty or missing `changed` map keeps the old behaviour.
+ * syncs (#34, docs/device-sync.md "Triggers"). Without a mail type there is
+ * nothing to notify, and the legacy path (the newest unread mail) must not
+ * run for it. An empty or missing `changed` map keeps the old behaviour.
  */
 export function carriesNoMail(payload: RelayPushData): boolean {
   if (payload.kind !== 'jmap-state-change' || !payload.changed) return false;
   const accounts = Object.values(payload.changed);
   if (accounts.length === 0) return false;
-  return !accounts.some((types) => !!types && typeof types === 'object' && 'EmailDelivery' in types);
+  return !accounts.some((types) => !!types && typeof types === 'object'
+    && MAIL_TYPES.some((type) => type in types));
 }
 
 // Fired by BulwarkPushTaskService when a data FCM message arrives. Runs in a