chore: update version number to 0.1.30

App.tsx

@@ -15,7 +15,7 @@ import {
   getInitialNotificationTap,
   getStoredRelayBaseUrl,
   setupPushNotifications,
-  teardownPushNotifications,
+  teardownPushNotificationsForAccount,
   type NotificationTapPayload,
 } from './src/lib/push-notifications';
 import type { MainTabsParamList, RootStackParamList } from './src/navigation/types';
@@ -51,8 +51,21 @@ const Stack = createNativeStackNavigator<RootStackParamList>();
 const Tab = createBottomTabNavigator<MainTabsParamList>();
 const navigationRef = createNavigationContainerRef<RootStackParamList>();
 
-function navigateToNotificationTap(payload: NotificationTapPayload): void {
+async function navigateToNotificationTap(payload: NotificationTapPayload): Promise<void> {
   if (!navigationRef.isReady()) return;
+
+  // The notification carries the account it was generated for. If the user
+  // has since switched to a different account (or had a different one active
+  // when the notification arrived), opening EmailThread under the active
+  // account would fetch the email from the wrong server and fail.
+  const auth = useAuthStore.getState();
+  if (payload.accountId && payload.accountId !== auth.activeAccountId) {
+    const account = useAccountStore.getState().getAccountById(payload.accountId);
+    if (!account) return; // account was logged out — nothing safe to open.
+    await auth.switchAccount(payload.accountId);
+    if (useAuthStore.getState().activeAccountId !== payload.accountId) return;
+  }
+
   navigationRef.navigate('EmailThread', {
     emailId: payload.emailId,
     threadId: payload.threadId,
@@ -261,11 +274,11 @@ export default function App() {
     void (async () => {
       const initial = await getInitialNotificationTap();
       if (cancelled || !initial) return;
-      navigateToNotificationTap(initial);
+      await navigateToNotificationTap(initial);
     })();
 
     const unsubscribe = addNotificationTapListener((payload) => {
-      navigateToNotificationTap(payload);
+      void navigateToNotificationTap(payload);
     });
 
     return () => {
@@ -276,18 +289,24 @@ export default function App() {
 
   // Re-register the device with the configured relay once authenticated,
   // and whenever the FCM token rotates. Honours the user's notification
-  // preference - flipping it off tears down the active subscription so the
-  // FirebaseMessagingService stops receiving pings for this device.
+  // preference - flipping it off tears down THIS account's subscription so
+  // notifications stop arriving for it. Other logged-in accounts keep their
+  // setups intact.
   const emailNotificationsEnabled = useSettingsStore(
     (s) => s.emailNotificationsEnabled,
   );
+  const activeAccountId = useAuthStore((s) => s.activeAccountId);
   React.useEffect(() => {
     if (!isAuthenticated || !client) return;
 
     let cancelled = false;
     const doSetup = async () => {
       if (!emailNotificationsEnabled) {
-        await teardownPushNotifications().catch(() => undefined);
+        if (activeAccountId) {
+          await teardownPushNotificationsForAccount(activeAccountId).catch(
+            () => undefined,
+          );
+        }
         return;
       }
       const relayBaseUrl = await getStoredRelayBaseUrl();
@@ -315,7 +334,7 @@ export default function App() {
       cancelled = true;
       unsubscribe();
     };
-  }, [client, isAuthenticated, emailNotificationsEnabled]);
+  }, [client, isAuthenticated, emailNotificationsEnabled, activeAccountId]);
 
   React.useEffect(() => {
     if (!isAuthenticated || !client) {

VERSION

@@ -1 +1 @@
-0.1.22
+0.1.30

android/app/src/main/AndroidManifest.xml

@@ -2,11 +2,9 @@
   <uses-permission android:name="android.permission.INTERNET"/>
   <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
   <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
-  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
-  <uses-permission android:name="android.permission.RECORD_AUDIO"/>
-  <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
+  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" android:maxSdkVersion="32"/>
+  <uses-permission android:name="android.permission.READ_MEDIA_IMAGES"/>
   <uses-permission android:name="android.permission.VIBRATE"/>
-  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
   <queries>
     <intent>
       <action android:name="android.intent.action.VIEW"/>

android/app/src/main/java/com/anonymous/bulwarkmobile/BulwarkFcmModule.kt

@@ -19,6 +19,7 @@ import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.bridge.WritableMap
 import com.facebook.react.modules.core.DeviceEventManagerModule.RCTDeviceEventEmitter
 import com.google.firebase.messaging.FirebaseMessaging
+import java.io.ByteArrayOutputStream
 import java.net.HttpURLConnection
 import java.net.URL
 import kotlin.concurrent.thread
@@ -64,6 +65,7 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
         val emailId = options.getString("emailId")
         val threadId = options.getString("threadId")
         val subject = options.takeIf { it.hasKey("subject") }?.getString("subject")
+        val accountId = options.takeIf { it.hasKey("accountId") }?.getString("accountId")
 
         // Bitmap fetch + draw off the bridge thread so the caller doesn't
         // block waiting for the favicon request.
@@ -72,7 +74,7 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
                 ?: makeLetterAvatar(initials, bgColorHex)
             postNotification(
                 notificationId, title, body, largeIcon, bgColorHex,
-                emailId, threadId, subject,
+                emailId, threadId, subject, accountId,
             )
             promise.resolve(null)
         }
@@ -93,6 +95,7 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
         emailId: String?,
         threadId: String?,
         subject: String?,
+        accountId: String?,
     ) {
         val ctx = reactApplicationContext
         val intent = Intent(ctx, MainActivity::class.java).apply {
@@ -100,6 +103,7 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
             if (emailId != null) putExtra(NotificationTapStore.EXTRA_EMAIL_ID, emailId)
             if (threadId != null) putExtra(NotificationTapStore.EXTRA_THREAD_ID, threadId)
             if (subject != null) putExtra(NotificationTapStore.EXTRA_SUBJECT, subject)
+            if (accountId != null) putExtra(NotificationTapStore.EXTRA_ACCOUNT_ID, accountId)
         }
         val pending = PendingIntent.getActivity(
             ctx,
@@ -148,7 +152,36 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
         conn.readTimeout = 3000
         conn.instanceFollowRedirects = true
         conn.setRequestProperty("User-Agent", "bulwark-mobile")
-        conn.inputStream.use { BitmapFactory.decodeStream(it) }
+        // Cap the response to MAX_FAVICON_BYTES so a hostile / misconfigured
+        // server can't OOM the headless task with a multi-megabyte image.
+        // We also sample down to ~256x256 since it'll only render at 192px.
+        val stream = conn.inputStream
+        val bytes = stream.use { input ->
+            val limit = MAX_FAVICON_BYTES
+            val buf = ByteArrayOutputStream()
+            val chunk = ByteArray(8 * 1024)
+            var total = 0
+            while (true) {
+                val n = input.read(chunk)
+                if (n <= 0) break
+                total += n
+                if (total > limit) return@use null
+                buf.write(chunk, 0, n)
+            }
+            buf.toByteArray()
+        } ?: return null
+        val opts = BitmapFactory.Options().apply {
+            inJustDecodeBounds = true
+        }
+        BitmapFactory.decodeByteArray(bytes, 0, bytes.size, opts)
+        var sample = 1
+        while ((opts.outWidth / sample) > 384 || (opts.outHeight / sample) > 384) {
+            sample *= 2
+        }
+        val decodeOpts = BitmapFactory.Options().apply {
+            inSampleSize = sample
+        }
+        BitmapFactory.decodeByteArray(bytes, 0, bytes.size, decodeOpts)
     } catch (_: Exception) {
         null
     }
@@ -167,6 +200,9 @@ class BulwarkFcmModule(reactContext: ReactApplicationContext)
     fun removeListeners(count: Int) {}
 
     companion object {
+        // 1 MiB is plenty for a favicon; anything bigger is a sign of trouble.
+        private const val MAX_FAVICON_BYTES = 1 * 1024 * 1024
+
         @Volatile private var currentInstance: BulwarkFcmModule? = null
 
         fun emit(eventName: String, params: WritableMap?) {

android/app/src/main/java/com/anonymous/bulwarkmobile/NotificationTapStore.kt

@@ -17,17 +17,36 @@ object NotificationTapStore {
         return value
     }
 
+    // The activity is exported (required by the LAUNCHER intent filter), so
+    // any third-party app on the device can craft a starting intent that
+    // includes these extras. Reject anything that doesn't look like the IDs
+    // our notification builder writes — preventing other apps from
+    // navigating us to a forged email/thread.
+    private val ID_PATTERN = Regex("^[A-Za-z0-9_-]{1,128}$")
+    // accountId is `username@host` (see generateAccountId), so it needs `.`,
+    // `@`, `+` etc. — cap length and restrict charset to what that helper can
+    // emit. accountId is optional: notifications created before this field
+    // existed still navigate (using the active account as a fallback).
+    private val ACCOUNT_ID_PATTERN = Regex("^[A-Za-z0-9._+@-]{1,256}$")
+
     fun captureFromIntent(intent: Intent?): TapPayload? {
         val extras = intent?.extras ?: return null
-        val emailId = extras.getString(EXTRA_EMAIL_ID) ?: return null
-        val threadId = extras.getString(EXTRA_THREAD_ID) ?: return null
-        val subject = extras.getString(EXTRA_SUBJECT)
-        val payload = TapPayload(emailId, threadId, subject)
+        val emailId = extras.getString(EXTRA_EMAIL_ID)?.takeIf { ID_PATTERN.matches(it) }
+            ?: return null
+        val threadId = extras.getString(EXTRA_THREAD_ID)?.takeIf { ID_PATTERN.matches(it) }
+            ?: return null
+        // Subject is human-readable text and may legitimately contain anything;
+        // cap its length so a hostile launcher can't ship a 1MB string into
+        // the navigation payload.
+        val subject = extras.getString(EXTRA_SUBJECT)?.take(512)
+        val accountId = extras.getString(EXTRA_ACCOUNT_ID)?.takeIf { ACCOUNT_ID_PATTERN.matches(it) }
+        val payload = TapPayload(emailId, threadId, subject, accountId)
         pending = payload
         // Clear so a subsequent activity lifecycle event doesn't replay this.
         extras.remove(EXTRA_EMAIL_ID)
         extras.remove(EXTRA_THREAD_ID)
         extras.remove(EXTRA_SUBJECT)
+        extras.remove(EXTRA_ACCOUNT_ID)
         return payload
     }
 
@@ -35,15 +54,18 @@ object NotificationTapStore {
         val emailId: String,
         val threadId: String,
         val subject: String?,
+        val accountId: String?,
     ) {
         fun toMap(): WritableMap = Arguments.createMap().apply {
             putString("emailId", emailId)
             putString("threadId", threadId)
             if (subject != null) putString("subject", subject)
+            if (accountId != null) putString("accountId", accountId)
         }
     }
 
     const val EXTRA_EMAIL_ID = "bulwark.notification.emailId"
     const val EXTRA_THREAD_ID = "bulwark.notification.threadId"
     const val EXTRA_SUBJECT = "bulwark.notification.subject"
+    const val EXTRA_ACCOUNT_ID = "bulwark.notification.accountId"
 }

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.22",
+  "version": "0.1.30",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "bulwark-mobile",
-      "version": "0.1.22",
+      "version": "0.1.30",
       "license": "AGPL-3.0-only",
       "dependencies": {
         "@react-native-async-storage/async-storage": "2.2.0",
@@ -17,6 +17,7 @@
         "@react-navigation/native-stack": "^7.14.10",
         "date-fns": "^4.1.0",
         "expo": "~54.0.33",
+        "expo-document-picker": "~14.0.8",
         "expo-file-system": "~19.0.21",
         "expo-image-picker": "~17.0.10",
         "expo-intent-launcher": "~13.0.8",
@@ -5216,6 +5217,15 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-document-picker": {
+      "version": "14.0.8",
+      "resolved": "https://registry.npmjs.org/expo-document-picker/-/expo-document-picker-14.0.8.tgz",
+      "integrity": "sha512-3tyQKpPqWWFlI8p9RiMX1+T1Zge5mEKeBuXWp1h8PEItFMUDSiOJbQ112sfdC6Hxt8wSxreV9bCRl/NgBdt+fA==",
+      "license": "MIT",
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
     "node_modules/expo-file-system": {
       "version": "19.0.21",
       "resolved": "https://registry.npmjs.org/expo-file-system/-/expo-file-system-19.0.21.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.22",
+  "version": "0.1.30",
   "license": "AGPL-3.0-only",
   "main": "index.ts",
   "scripts": {
@@ -10,6 +10,7 @@
     "web": "expo start --web",
     "test": "vitest run",
     "test:watch": "vitest",
+    "typecheck": "tsc --noEmit",
     "bump": "node scripts/bump-version.mjs",
     "sync-locales": "node scripts/sync-locales.mjs"
   },
@@ -22,6 +23,7 @@
     "@react-navigation/native-stack": "^7.14.10",
     "date-fns": "^4.1.0",
     "expo": "~54.0.33",
+    "expo-document-picker": "~14.0.8",
     "expo-file-system": "~19.0.21",
     "expo-image-picker": "~17.0.10",
     "expo-intent-launcher": "~13.0.8",

src/api/__tests__/calendar.test.ts

@@ -4,6 +4,7 @@ vi.mock('../jmap-client', () => ({
   jmapClient: {
     accountId: 'acc-1',
     request: vi.fn(),
+    getMaxObjectsInGet: () => 500,
   },
 }));
 
@@ -41,7 +42,10 @@ describe('calendar operations', () => {
   });
 
   describe('queryEvents', () => {
-    it('should query events within date range', async () => {
+    it('should send a CalendarEvent/query without server-side filter', async () => {
+      // Stalwart rejects inCalendars/after/before, so we fetch unfiltered and
+      // filter client-side. Asserting on the absence of `filter` keeps that
+      // contract pinned.
       mockRequest.mockResolvedValue({
         methodResponses: [['CalendarEvent/query', { ids: ['ev1', 'ev2'] }, '0']],
       });
@@ -50,12 +54,9 @@ describe('calendar operations', () => {
       expect(result).toEqual(['ev1', 'ev2']);
 
       const call = mockRequest.mock.calls[0][0][0];
-      expect(call[1].filter).toEqual({
-        inCalendars: ['cal-1'],
-        after: '2026-03-01T00:00:00Z',
-        before: '2026-03-31T23:59:59Z',
-        types: ['Event'],
-      });
+      expect(call[0]).toBe('CalendarEvent/query');
+      expect(call[1].filter).toBeUndefined();
+      expect(call[1].accountId).toBe('acc-1');
     });
   });
 

src/api/__tests__/contacts.test.ts

@@ -4,6 +4,7 @@ vi.mock('../jmap-client', () => ({
   jmapClient: {
     accountId: 'acc-1',
     request: vi.fn(),
+    getMaxObjectsInGet: () => 500,
   },
 }));
 
@@ -50,14 +51,14 @@ describe('contacts operations', () => {
       expect(result).toEqual(['c1', 'c2']);
     });
 
-    it('should use default empty filter', async () => {
+    it('should omit filter when none provided', async () => {
       mockRequest.mockResolvedValue({
         methodResponses: [['ContactCard/query', { ids: [] }, '0']],
       });
 
       await queryContacts();
       const call = mockRequest.mock.calls[0][0][0];
-      expect(call[1].filter).toEqual({});
+      expect(call[1].filter).toBeUndefined();
     });
   });
 

src/api/__tests__/email.test.ts

@@ -90,6 +90,24 @@ describe('email operations', () => {
       const call = mockRequest.mock.calls[0][0][0];
       expect(call[1].filter).toEqual({ inMailbox: 'mb-1', hasKeyword: '$flagged' });
     });
+
+    it('should AND-wrap a FilterOperator instead of spreading it', async () => {
+      mockRequest.mockResolvedValue({
+        methodResponses: [['Email/query', { ids: [], total: 0 }, '0']],
+      });
+
+      const userFilter = {
+        operator: 'AND',
+        conditions: [{ inMailbox: 'mb-1' }, { notKeyword: '$seen' }],
+      };
+      await queryEmails('mb-1', { filter: userFilter });
+
+      const call = mockRequest.mock.calls[0][0][0];
+      expect(call[1].filter).toEqual({
+        operator: 'AND',
+        conditions: [{ inMailbox: 'mb-1' }, userFilter],
+      });
+    });
   });
 
   describe('getEmails', () => {
@@ -197,7 +215,7 @@ describe('email operations', () => {
 
       expect(result).toEqual(['e1']);
       const call = mockRequest.mock.calls[0][0][0];
-      expect(call[1].filter).toEqual({ text: 'test query' });
+      expect(call[1].filter).toEqual({ text: 'test* query*' });
     });
 
     it('should include mailbox filter if specified', async () => {
@@ -208,7 +226,7 @@ describe('email operations', () => {
       await searchEmails('query', 'mb-1');
 
       const call = mockRequest.mock.calls[0][0][0];
-      expect(call[1].filter).toEqual({ text: 'query', inMailbox: 'mb-1' });
+      expect(call[1].filter).toEqual({ text: 'query*', inMailbox: 'mb-1' });
     });
   });
 

src/api/blob.ts

@@ -61,6 +61,57 @@ export async function uploadBlob(
   throw new Error('Upload succeeded but response did not include a blobId');
 }
 
+// Direct in-memory upload. The on-disk variant goes through expo-file-system's
+// `new File(uri).bytes()`, which is overkill when we already have the bytes
+// (e.g. the empty-blob trick used to create directories on Stalwart).
+export async function uploadBytes(
+  bytes: Uint8Array,
+  type: string,
+): Promise<{ blobId: string; size: number; type: string }> {
+  const session = jmapClient.currentSession;
+  if (!session) throw new Error('Not connected');
+
+  const uploadUrl = session.uploadUrl.replace(
+    '{accountId}',
+    encodeURIComponent(jmapClient.accountId),
+  );
+
+  const response = await secureFetch(uploadUrl, {
+    method: 'POST',
+    headers: {
+      'Content-Type': type || 'application/octet-stream',
+      Authorization: jmapClient.authHeader,
+    },
+    body: bytes.buffer as ArrayBuffer,
+  });
+
+  if (!response.ok) {
+    const detail = await response.text().catch(() => '');
+    throw new Error(`Upload failed: ${response.status}${detail ? ` ${detail}` : ''}`);
+  }
+
+  const raw = (await response.json()) as Record<string, unknown>;
+  const direct = raw as { blobId?: string; type?: string; size?: number };
+  if (typeof direct.blobId === 'string') {
+    return {
+      blobId: direct.blobId,
+      size: typeof direct.size === 'number' ? direct.size : bytes.byteLength,
+      type: typeof direct.type === 'string' && direct.type ? direct.type : type,
+    };
+  }
+  const nested = raw[jmapClient.accountId] as
+    | { blobId?: string; type?: string; size?: number }
+    | undefined;
+  if (nested?.blobId) {
+    return {
+      blobId: nested.blobId,
+      size: typeof nested.size === 'number' ? nested.size : bytes.byteLength,
+      type: typeof nested.type === 'string' && nested.type ? nested.type : type,
+    };
+  }
+  throw new Error('Upload succeeded but response did not include a blobId');
+}
+
 export function getDownloadUrl(
   blobId: string,
   name?: string,

src/api/email.ts

@@ -93,10 +93,22 @@ export async function queryEmails(
   },
 ): Promise<{ ids: string[]; total: number }> {
   const accountId = jmapClient.accountId;
+  const inMailbox = { inMailbox: mailboxId };
+  const userFilter = options?.filter;
+  // JMAP filters are either a FilterCondition or a FilterOperator (operator +
+  // conditions) — never both. Spreading a FilterOperator next to `inMailbox`
+  // produces a hybrid object that servers reduce to the FilterCondition,
+  // silently dropping the operator's conditions (e.g. the "unread" toggle).
+  const filter =
+    !userFilter || Object.keys(userFilter).length === 0
+      ? inMailbox
+      : 'operator' in userFilter
+        ? { operator: 'AND', conditions: [inMailbox, userFilter] }
+        : { ...inMailbox, ...userFilter };
   const res = await jmapClient.request([
     ['Email/query', {
       accountId,
-      filter: { inMailbox: mailboxId, ...options?.filter },
+      filter,
       sort: options?.sort ?? [{ property: 'receivedAt', isAscending: false }],
       position: options?.position ?? 0,
       limit: options?.limit ?? 50,

src/api/files.ts

@@ -1,19 +1,68 @@
 import { jmapClient } from './jmap-client';
 import { CAPABILITIES } from './types';
 import type { FileNode } from './types';
+import { getDownloadUrl, uploadBlob, uploadBytes } from './blob';
 
-const USING = [CAPABILITIES.CORE, CAPABILITIES.MAIL];
+const USING = [CAPABILITIES.CORE, CAPABILITIES.FILES];
 
-export async function getFileNodes(parentId?: string | null): Promise<FileNode[]> {
+// Stalwart and other JMAP servers use one of these strings on FileNode.type to
+// mark a directory; everything else is a MIME type.
+const DIRECTORY_TYPES = new Set([
+  'd',
+  'application/x-directory',
+  'text/directory',
+  'httpd/unix-directory',
+  'inode/directory',
+]);
+
+export function isDirectory(node: Pick<FileNode, 'type'>): boolean {
+  const t = node.type;
+  if (!t) return false;
+  return DIRECTORY_TYPES.has(t) || t.includes('directory');
+}
+
+// Stalwart rejects `/` in FileNode names, so the webmail (and now this app)
+// uses U+2215 DIVISION SLASH as the path separator inside the flat `name`
+// field. Hierarchy is encoded into the name — there is no `parentId` nesting.
+// e.g. a file inside the `Documents` folder is stored with
+// `name = "Documents∕report.pdf"`. The display name shown to the user
+// strips the prefix.
+export const PATH_SEP = '∕';
+
+// Path is a list of folder display names from root. [] is root,
+// ['Documents'] is inside Documents, ['Documents','sub'] is inside the
+// `sub` folder under Documents.
+export function pathToPrefix(path: readonly string[]): string {
+  if (path.length === 0) return '';
+  return path.join(PATH_SEP) + PATH_SEP;
+}
+
+// True when `node` is a direct child (not a descendant) of `prefix`.
+export function isDirectChildOfPrefix(node: Pick<FileNode, 'name'>, prefix: string): boolean {
+  if (!node.name) return false;
+  if (prefix === '') return !node.name.includes(PATH_SEP);
+  if (!node.name.startsWith(prefix)) return false;
+  const rest = node.name.slice(prefix.length);
+  return rest.length > 0 && !rest.includes(PATH_SEP);
+}
+
+export function nodeDisplayName(node: Pick<FileNode, 'name'>, prefix: string): string {
+  return prefix && node.name.startsWith(prefix) ? node.name.slice(prefix.length) : node.name;
+}
+
+// Stalwart's FileNode/get does not support a parentId filter and some builds
+// omit `type` from the default property set. We fetch the whole tree and
+// filter client-side; properties are listed explicitly so `isDirectory()`
+// always has a value to look at.
+const FILE_NODE_PROPERTIES = ['id', 'parentId', 'name', 'type', 'blobId', 'size', 'created', 'updated'];
+
+export async function getAllFileNodes(): Promise<FileNode[]> {
   const accountId = jmapClient.accountId;
-  const filter: Record<string, unknown> = {};
-  if (parentId !== undefined) filter.parentId = parentId;
-
   const res = await jmapClient.request(
-    [['FileNode/get', { accountId, filter }, '0']],
+    [['FileNode/get', { accountId, ids: null, properties: FILE_NODE_PROPERTIES }, '0']],
     USING,
   );
-  return res.methodResponses[0][1].list;
+  return (res.methodResponses[0][1].list ?? []) as FileNode[];
 }
 
 export async function createFileNode(
@@ -27,13 +76,113 @@ export async function createFileNode(
     }, '0']],
     USING,
   );
-  return res.methodResponses[0][1].created['new-file'];
+  const created = res.methodResponses[0][1].created?.['new-file'];
+  if (!created) {
+    const err = res.methodResponses[0][1].notCreated?.['new-file'];
+    throw new Error(err?.description || 'Create failed');
+  }
+  return created;
+}
+
+export async function createFolder(
+  displayName: string,
+  currentPath: readonly string[],
+): Promise<FileNode> {
+  // Stalwart's FileNode/set rejects directory creates without a blobId
+  // ("Missing blob id"), so we upload an empty blob first and reference it.
+  // Mirrors the webmail's createFileDirectory.
+  const blob = await uploadBytes(new Uint8Array(0), 'application/x-directory');
+  const fullName = pathToPrefix(currentPath) + displayName;
+  return createFileNode({ name: fullName, type: 'd', blobId: blob.blobId, size: 0 });
+}
+
+export async function updateFileNode(
+  id: string,
+  updates: Partial<Pick<FileNode, 'name' | 'parentId'>>,
+): Promise<void> {
+  const accountId = jmapClient.accountId;
+  const res = await jmapClient.request(
+    [['FileNode/set', { accountId, update: { [id]: updates } }, '0']],
+    USING,
+  );
+  const notUpdated = res.methodResponses[0][1].notUpdated?.[id];
+  if (notUpdated) throw new Error(notUpdated.description || 'Update failed');
+}
+
+// Rename a node and, if it's a folder, cascade the rename to every descendant
+// so the encoded path stays consistent. The webmail does this same dance.
+export async function renameFileNode(
+  node: FileNode,
+  newDisplayName: string,
+  currentPath: readonly string[],
+  allNodes: readonly FileNode[],
+): Promise<void> {
+  const prefix = pathToPrefix(currentPath);
+  const oldServerName = node.name;
+  const newServerName = prefix + newDisplayName;
+  if (oldServerName === newServerName) return;
+
+  await updateFileNode(node.id, { name: newServerName });
+
+  if (isDirectory(node)) {
+    const oldFolderPrefix = oldServerName + PATH_SEP;
+    const newFolderPrefix = newServerName + PATH_SEP;
+    for (const n of allNodes) {
+      if (n.id === node.id) continue;
+      if (n.name.startsWith(oldFolderPrefix)) {
+        await updateFileNode(n.id, { name: newFolderPrefix + n.name.slice(oldFolderPrefix.length) });
+      }
+    }
+  }
 }
 
 export async function deleteFileNodes(ids: string[]): Promise<void> {
+  if (ids.length === 0) return;
   const accountId = jmapClient.accountId;
   await jmapClient.request(
     [['FileNode/set', { accountId, destroy: ids }, '0']],
     USING,
   );
 }
+
+// Delete `targets` and every descendant. Stalwart doesn't enforce parent
+// references, so we collect descendants by name-prefix and destroy them all
+// in one call. Without this, deleting a folder leaves its files orphaned and
+// still discoverable at the old encoded path.
+export async function deleteWithDescendants(
+  targets: readonly FileNode[],
+  allNodes: readonly FileNode[],
+): Promise<void> {
+  const ids = new Set<string>();
+  for (const node of targets) {
+    ids.add(node.id);
+    if (isDirectory(node)) {
+      const folderPrefix = node.name + PATH_SEP;
+      for (const n of allNodes) {
+        if (n.name.startsWith(folderPrefix)) ids.add(n.id);
+      }
+    }
+  }
+  await deleteFileNodes(Array.from(ids));
+}
+
+export function getFileNodeDownloadUrl(node: FileNode): string {
+  if (!node.blobId) throw new Error('Folders cannot be downloaded');
+  return getDownloadUrl(node.blobId, node.name, node.type);
+}
+
+export async function uploadFileNode(
+  uri: string,
+  displayName: string,
+  mimeType: string,
+  currentPath: readonly string[],
+): Promise<FileNode> {
+  const blob = await uploadBlob(uri, mimeType);
+  const fullName = pathToPrefix(currentPath) + displayName;
+  return createFileNode({
+    name: fullName,
+    type: blob.type || mimeType || 'application/octet-stream',
+    blobId: blob.blobId,
+    size: blob.size,
+  });
+}

src/api/push.ts

@@ -201,13 +201,35 @@ export function startPolling(
   return () => clearInterval(timer);
 }
 
+export interface StartPushOptions {
+  onStateChange: StateChangeHandler;
+  onError?: (error: Error) => void;
+}
+
 /**
- * Start real-time updates, preferring SSE with polling fallback.
+ * Start real-time updates, preferring SSE with polling fallback. The `_client`
+ * argument is unused today (the underlying event source uses the singleton
+ * `jmapClient`) but is part of the call signature so the host App can pass
+ * the active client reference and trigger React re-runs on account switch.
  */
 export function startPushUpdates(
-  onStateChange: StateChangeHandler,
+  _client: unknown,
+  opts: StartPushOptions,
 ): () => void {
-  const cleanup = connectEventSource(onStateChange);
-  if (cleanup) return cleanup;
-  return startPolling(onStateChange);
+  const onError = opts.onError;
+  const safeOnStateChange: StateChangeHandler = (change) => {
+    try {
+      opts.onStateChange(change);
+    } catch (err) {
+      if (onError) onError(err instanceof Error ? err : new Error(String(err)));
+    }
+  };
+  try {
+    const cleanup = connectEventSource(safeOnStateChange);
+    if (cleanup) return cleanup;
+    return startPolling(safeOnStateChange);
+  } catch (err) {
+    if (onError) onError(err instanceof Error ? err : new Error(String(err)));
+    return () => undefined;
+  }
 }

src/api/types.ts

@@ -429,7 +429,7 @@ export interface FileNode {
   name: string;
   parentId?: string | null;
   type: string;
-  blobId?: string;
+  blobId?: string | null;
   size?: number;
   created?: string;
   updated?: string;
@@ -465,4 +465,5 @@ export const CAPABILITIES = {
   CALENDARS: 'urn:ietf:params:jmap:calendars',
   SIEVE: 'urn:ietf:params:jmap:sieve',
   QUOTA: 'urn:ietf:params:jmap:quota',
+  FILES: 'urn:ietf:params:jmap:filenode',
 } as const;

src/api/updates.ts

@@ -13,6 +13,45 @@ export interface LatestRelease {
   publishedAt: string;
   body: string;
   apkAsset: ReleaseAsset | null;
+  // Lower-case hex SHA-256 of the APK, parsed from a `*.apk.sha256` companion
+  // asset or from the release body. Null when the release didn't publish one;
+  // the installer falls back to relying solely on Android's package signing
+  // check in that case (still strong, but less defense-in-depth).
+  apkSha256: string | null;
+}
+
+const SHA256_RE = /\b([a-f0-9]{64})\b/i;
+
+function extractSha256(body: string, apkName: string | undefined): string | null {
+  if (!body) return null;
+  // Prefer a line that explicitly references the APK so we don't pick up the
+  // hash of an unrelated asset.
+  const lines = body.split(/\r?\n/);
+  if (apkName) {
+    for (const line of lines) {
+      if (line.includes(apkName)) {
+        const m = SHA256_RE.exec(line);
+        if (m) return m[1].toLowerCase();
+      }
+    }
+  }
+  // Fallback: a single SHA256 anywhere in the body — common when the release
+  // notes just list one checksum.
+  const m = SHA256_RE.exec(body);
+  return m ? m[1].toLowerCase() : null;
+}
+
+async function fetchCompanionSha256(asset: ReleaseAsset | undefined): Promise<string | null> {
+  if (!asset) return null;
+  try {
+    const res = await fetch(asset.browser_download_url);
+    if (!res.ok) return null;
+    const text = await res.text();
+    const m = SHA256_RE.exec(text);
+    return m ? m[1].toLowerCase() : null;
+  } catch {
+    return null;
+  }
 }
 
 export async function fetchLatestRelease(repo: string = UPDATE_REPO): Promise<LatestRelease | null> {
@@ -32,6 +71,14 @@ export async function fetchLatestRelease(repo: string = UPDATE_REPO): Promise<La
     assets: ReleaseAsset[];
   };
   const apkAsset = json.assets.find((a) => a.name.endsWith('.apk')) ?? null;
+  const sha256Asset = apkAsset
+    ? json.assets.find(
+        (a) => a.name === `${apkAsset.name}.sha256` || a.name === `${apkAsset.name}.SHA256`,
+      )
+    : undefined;
+  const apkSha256 =
+    (await fetchCompanionSha256(sha256Asset)) ??
+    extractSha256(json.body || '', apkAsset?.name);
   return {
     tag: json.tag_name,
     name: json.name || json.tag_name,
@@ -39,5 +86,6 @@ export async function fetchLatestRelease(repo: string = UPDATE_REPO): Promise<La
     publishedAt: json.published_at,
     body: json.body || '',
     apkAsset,
+    apkSha256,
   };
 }

src/components/EmailBodyView.tsx

@@ -297,7 +297,7 @@ export default function EmailBodyView({ email, senderEmail }: EmailBodyViewProps
       <View style={[styles.webContainer, { height }]}>
         <WebView
           ref={webviewRef}
-          originWhitelist={['about:*']}
+          originWhitelist={['about:blank']}
           source={source}
           javaScriptEnabled
           injectedJavaScript={HEIGHT_REPORTER}

src/components/OfflineCacheBanner.tsx

@@ -3,8 +3,10 @@
 
 import React from 'react';
 import { View, Text, StyleSheet, Pressable } from 'react-native';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
 import { CloudDownload, X } from 'lucide-react-native';
 import { useOfflineCacheStore } from '../stores/offline-cache-store';
+import { useUpdatesStore } from '../stores/updates-store';
 import { formatBytes } from '../lib/offline-sync';
 import { spacing, radius, typography, type ThemePalette } from '../theme/tokens';
 import { useColors } from '../theme/colors';
@@ -12,9 +14,18 @@ import { useColors } from '../theme/colors';
 export function OfflineCacheBanner(): React.ReactElement | null {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
+  const insets = useSafeAreaInsets();
   const sync = useOfflineCacheStore((s) => s.sync);
   const requestAbort = useOfflineCacheStore((s) => s.requestAbort);
   const resetSync = useOfflineCacheStore((s) => s.resetSync);
+  // When UpdateBanner is stacked above us it already absorbs the status-bar
+  // inset, so we only add it when we're the topmost banner.
+  const cachedLatest = useUpdatesStore((s) => s.cachedLatest);
+  const dismissedTag = useUpdatesStore((s) => s.dismissedTag);
+  const hasUpdate = useUpdatesStore((s) => s.hasUpdate);
+  const updateBannerVisible =
+    hasUpdate() && cachedLatest?.apkAsset != null && dismissedTag !== cachedLatest.tag;
+  const topInset = updateBannerVisible ? 0 : insets.top;
   const [hideTimer, setHideTimer] = React.useState<ReturnType<typeof setTimeout> | null>(null);
 
   // Auto-dismiss the "done" state after a few seconds so the bar isn't a
@@ -71,7 +82,7 @@ export function OfflineCacheBanner(): React.ReactElement | null {
   const isError = sync.phase === 'error';
 
   return (
-    <View style={[styles.banner, isError && styles.bannerError]}>
+    <View style={[styles.banner, isError && styles.bannerError, { paddingTop: spacing.sm + topInset }]}>
       <CloudDownload size={16} color={c.primaryForeground} />
       <View style={{ flex: 1 }}>
         <Text style={styles.title}>{title}</Text>

src/components/RichTextEditor.tsx

@@ -263,20 +263,30 @@ function buildEditorHtml(opts: {
     },
     insertLink: function (url, label) {
       editor.focus();
+      // Reject anything that isn't a safe scheme or an absolute path, so the
+      // user can't accidentally (or via a malicious paste) ship a
+      // javascript:/data: link to their recipient.
+      var safeSchemeRe = /^(https?:|mailto:|tel:|sms:|\/|\?|#)/i;
+      var trimmed = (url || '').trim();
+      if (!trimmed || !safeSchemeRe.test(trimmed)) return;
       var sel = window.getSelection();
       var hasSelection = sel && sel.rangeCount && !sel.getRangeAt(0).collapsed;
       if (hasSelection) {
-        try { document.execCommand('createLink', false, url); } catch (e) {}
+        try { document.execCommand('createLink', false, trimmed); } catch (e) {}
         // execCommand doesn't set rel; tag every anchor that points at this URL.
         Array.prototype.forEach.call(editor.getElementsByTagName('a'), function (a) {
-          if (a.getAttribute('href') === url) {
+          if (a.getAttribute('href') === trimmed) {
             a.setAttribute('rel', 'noopener noreferrer nofollow');
           }
         });
       } else {
-        var text = label && label.trim() ? label : url;
+        var text = label && label.trim() ? label : trimmed;
         var safe = text.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
-        var safeUrl = url.replace(/"/g, '&quot;');
+        var safeUrl = trimmed
+          .replace(/&/g, '&amp;')
+          .replace(/"/g, '&quot;')
+          .replace(/</g, '&lt;')
+          .replace(/>/g, '&gt;');
         var html = '<a href="' + safeUrl + '" rel="noopener noreferrer nofollow">' + safe + '</a>';
         try { document.execCommand('insertHTML', false, html); } catch (e) {}
       }
@@ -409,7 +419,7 @@ const RichTextEditor = React.forwardRef<RichTextEditorHandle, Props>(function Ri
     <View style={[styles.container, { height }]}>
       <WebView
         ref={webViewRef}
-        originWhitelist={['about:*']}
+        originWhitelist={['about:blank']}
         source={{ html }}
         onMessage={onMessage}
         javaScriptEnabled
@@ -433,9 +443,11 @@ const RichTextEditor = React.forwardRef<RichTextEditorHandle, Props>(function Ri
         style={styles.webview}
         containerStyle={styles.webviewContainer}
         onShouldStartLoadWithRequest={(request) => {
-          // Allow only the initial about:blank doc + data URIs we emit ourselves.
+          // Allow only the initial about:blank doc + data URIs we emit
+          // ourselves. Reject `about:*` (e.g. about:srcdoc) and every other
+          // scheme so a paste-injected anchor can't navigate the editor.
           const url = request.url;
-          return !url || url === 'about:blank' || url.startsWith('data:') || url.startsWith('about:');
+          return !url || url === 'about:blank' || url.startsWith('data:');
         }}
       />
     </View>

src/components/settings/NotificationSettings.tsx

@@ -17,9 +17,10 @@ import { useSettingsStore, type NotificationSound } from '../../stores/settings-
 import {
   DEFAULT_RELAY_BASE_URL,
   getStoredRelayBaseUrl,
+  readPushAccountIds,
   setStoredRelayBaseUrl,
   setupPushNotifications,
-  teardownPushNotifications,
+  teardownPushNotificationsForAccount,
 } from '../../lib/push-notifications';
 
 const SOUNDS: { value: NotificationSound; label: string }[] = [
@@ -40,6 +41,7 @@ export function NotificationSettings() {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
   const username = useAuthStore((s) => s.username);
+  const activeAccountId = useAuthStore((s) => s.activeAccountId);
 
   const hydrated = useSettingsStore((s) => s.hydrated);
   const hydrate = useSettingsStore((s) => s.hydrate);
@@ -106,10 +108,20 @@ export function NotificationSettings() {
     setConfirmDisable(false);
     setPushStatus({ kind: 'busy', message: 'Disabling…' });
     try {
-      await teardownPushNotifications();
-      await setStoredRelayBaseUrl(null);
-      setRelayUrl(DEFAULT_RELAY_BASE_URL);
-      setHasSaved(false);
+      if (activeAccountId) {
+        await teardownPushNotificationsForAccount(activeAccountId);
+      }
+      // The relay base URL is a device-wide setting shared with any other
+      // accounts that are still using push. Only clear it (and reset the UI
+      // to "not configured") when no accounts are using push any more —
+      // otherwise the remaining accounts would lose their relay URL and
+      // their next setup attempt would no-op.
+      const remaining = await readPushAccountIds();
+      if (remaining.length === 0) {
+        await setStoredRelayBaseUrl(null);
+        setRelayUrl(DEFAULT_RELAY_BASE_URL);
+        setHasSaved(false);
+      }
       setPushStatus({ kind: 'idle' });
     } catch (error) {
       setPushStatus({

src/lib/install-update.ts

@@ -3,12 +3,18 @@ import { File, Paths } from 'expo-file-system';
 import * as FileSystemLegacy from 'expo-file-system/legacy';
 import * as IntentLauncher from 'expo-intent-launcher';
 import type { ReleaseAsset } from '../api/updates';
+import { Sha256 } from './sha256';
 
 const FLAG_GRANT_READ_URI_PERMISSION = 0x00000001;
 const FLAG_ACTIVITY_NEW_TASK = 0x10000000;
 
+// Bytes per file-read chunk while computing the post-download SHA-256. Larger
+// chunks are faster but balloon the JS string buffer (base64 reads on this
+// platform). 256 KiB keeps memory bounded while still amortising the bridge.
+const HASH_CHUNK_BYTES = 256 * 1024;
+
 export interface InstallProgress {
-  phase: 'downloading' | 'installing';
+  phase: 'downloading' | 'verifying' | 'installing';
   /** 0-1 during download; undefined for installing phase */
   progress?: number;
   /** Bytes received during current download */
@@ -19,10 +25,51 @@ export interface InstallProgress {
 
 export type InstallProgressListener = (p: InstallProgress) => void;
 
+export interface InstallParams {
+  asset: ReleaseAsset;
+  /** Optional lower-case hex SHA-256. When present, mismatched downloads abort. */
+  expectedSha256?: string | null;
+}
+
+function base64ToBytes(b64: string): Uint8Array {
+  const bin = globalThis.atob ? globalThis.atob(b64) : atob(b64);
+  const out = new Uint8Array(bin.length);
+  for (let i = 0; i < bin.length; i++) out[i] = bin.charCodeAt(i);
+  return out;
+}
+
+async function hashFile(uri: string, totalBytes: number, onProgress?: InstallProgressListener): Promise<string> {
+  const hasher = new Sha256();
+  let offset = 0;
+  while (offset < totalBytes || totalBytes === 0) {
+    const length = Math.min(HASH_CHUNK_BYTES, totalBytes ? totalBytes - offset : HASH_CHUNK_BYTES);
+    const chunkB64 = await FileSystemLegacy.readAsStringAsync(uri, {
+      encoding: FileSystemLegacy.EncodingType.Base64,
+      position: offset,
+      length,
+    });
+    if (!chunkB64) break;
+    const bytes = base64ToBytes(chunkB64);
+    if (bytes.length === 0) break;
+    hasher.update(bytes);
+    offset += bytes.length;
+    if (totalBytes > 0) {
+      onProgress?.({ phase: 'verifying', progress: offset / totalBytes });
+    }
+    if (bytes.length < length) break;
+  }
+  return hasher.digestHex();
+}
+
 export async function downloadAndInstallApk(
-  asset: ReleaseAsset,
+  params: InstallParams | ReleaseAsset,
   onProgress?: InstallProgressListener,
 ): Promise<void> {
+  // Backwards-compat: callers used to pass the asset directly. Promote to the
+  // params shape so the verification path is opt-in by passing a checksum.
+  const { asset, expectedSha256 }: InstallParams =
+    'asset' in params ? params : { asset: params, expectedSha256: null };
+
   if (Platform.OS !== 'android') {
     throw new Error('APK install is only supported on Android');
   }
@@ -53,6 +100,33 @@ export async function downloadAndInstallApk(
     throw new Error('APK download failed');
   }
 
+  // Size sanity check. GitHub's `assets[].size` is signed by their TLS cert,
+  // so a byte-count mismatch is a strong signal the file was truncated /
+  // tampered with in transport. Cheap to compute, fail-fast.
+  const info = await FileSystemLegacy.getInfoAsync(result.uri);
+  const actualSize = (info as { size?: number }).size ?? 0;
+  if (asset.size > 0 && actualSize !== asset.size) {
+    await tryDelete(result.uri);
+    throw new Error(
+      `APK size mismatch: expected ${asset.size} bytes, got ${actualSize}`,
+    );
+  }
+
+  // SHA-256 verification when the release publishes one. Without it, we still
+  // get Android's package-signer check at install time — which rejects an APK
+  // signed with a different key — but that fails late (after the user sees a
+  // confusing system dialog). Bailing here surfaces the problem cleanly.
+  if (expectedSha256) {
+    onProgress?.({ phase: 'verifying', progress: 0 });
+    const actual = await hashFile(result.uri, actualSize || asset.size, onProgress);
+    if (actual.toLowerCase() !== expectedSha256.toLowerCase()) {
+      await tryDelete(result.uri);
+      throw new Error(
+        `APK checksum mismatch: expected ${expectedSha256}, got ${actual}`,
+      );
+    }
+  }
+
   onProgress?.({ phase: 'installing' });
 
   const contentUri = await FileSystemLegacy.getContentUriAsync(result.uri);
@@ -64,6 +138,14 @@ export async function downloadAndInstallApk(
   });
 }
 
+async function tryDelete(uri: string): Promise<void> {
+  try {
+    await FileSystemLegacy.deleteAsync(uri, { idempotent: true });
+  } catch {
+    /* best effort */
+  }
+}
+
 /**
  * Open the system "Install unknown apps" settings page for this app, so the
  * user can grant permission to install APKs from the package installer.

src/lib/push-background-task.ts

@@ -8,13 +8,22 @@ import {
   getFaviconDomain,
   getFaviconUrl,
 } from './avatar-utils';
+import {
+  deviceClientIdKey,
+  lastNotifiedKey,
+  migrateLegacyPushKeys,
+  readPushAccountIds,
+} from './push-notifications';
 
-const PUSH_ACCOUNT_ID_KEY = 'push:accountId:v1';
-const LAST_NOTIFIED_EMAIL_ID_KEY = 'push:lastNotifiedEmailId:v1';
 // Mirrors STORAGE_KEY in `stores/settings-store.ts`. The headless task can't
 // import the Zustand store (would pull in React) so we read AsyncStorage
 // directly. Keep this in sync if the store key ever changes.
 const SETTINGS_STORAGE_KEY = 'webmail:settings:v1';
+// Mirrors the persist name in `stores/account-store.ts`. We use it to find
+// the user's active account at the end of the headless task so we can leave
+// the jmapClient singleton in a state consistent with what the UI expects
+// when the app resumes.
+const ACCOUNT_REGISTRY_KEY = 'account-registry';
 
 interface PushPersistedSettings {
   emailNotificationsEnabled?: boolean;
@@ -41,76 +50,151 @@ interface ShowNotificationOptions {
   emailId: string;
   threadId: string;
   subject?: string;
+  accountId: string;
 }
 
 interface BulwarkFcmNative {
   showNotification(opts: ShowNotificationOptions): Promise<void>;
 }
 
+// The relay forwards each JMAP push to FCM tagged with the deviceClientId it
+// received the push on (the URL slot from createPushSubscription). The exact
+// key the relay uses isn't part of any client-controlled contract, so rather
+// than guessing a field name we scan all string values in the data payload
+// and look for one that matches a deviceClientId we've registered locally.
+// Returns null if nothing matches (e.g. legacy relay payload format) so the
+// caller falls back to iterating every known account.
+async function identifyAccountFromFcmData(
+  data: unknown,
+  accountIds: string[],
+): Promise<string | null> {
+  if (!data || typeof data !== 'object') return null;
+
+  const reverseMap = new Map<string, string>();
+  for (const accountId of accountIds) {
+    const dcid = await AsyncStorage.getItem(deviceClientIdKey(accountId));
+    if (dcid) reverseMap.set(dcid, accountId);
+  }
+  if (reverseMap.size === 0) return null;
+
+  for (const value of Object.values(data as Record<string, unknown>)) {
+    if (typeof value === 'string') {
+      const match = reverseMap.get(value);
+      if (match) return match;
+    }
+  }
+  return null;
+}
+
+// Read the persisted active account directly from AsyncStorage (Zustand's
+// persist middleware stores the JSON-serialised state under its `name`).
+async function readActiveAccountId(): Promise<string | null> {
+  try {
+    const raw = await AsyncStorage.getItem(ACCOUNT_REGISTRY_KEY);
+    if (!raw) return null;
+    const parsed = JSON.parse(raw) as { state?: { activeAccountId?: string | null } };
+    return parsed.state?.activeAccountId ?? null;
+  } catch {
+    return null;
+  }
+}
+
 // Fired by BulwarkPushTaskService when a data FCM message arrives. Runs in a
 // short-lived headless JS runtime - keep it fast, catch all errors, and always
 // resolve so the native service can release its wake lock.
-export async function pushBackgroundTask(_data: unknown): Promise<void> {
+export async function pushBackgroundTask(data: unknown): Promise<void> {
+  let activeAccountId: string | null = null;
   try {
     if (!(await emailNotificationsAllowed())) return;
 
-    const accountId = await AsyncStorage.getItem(PUSH_ACCOUNT_ID_KEY);
-    if (!accountId) return;
+    await migrateLegacyPushKeys();
 
-    const loaded = await jmapClient.loadAccount(accountId);
-    if (!loaded) return;
+    const accountIds = await readPushAccountIds();
+    if (accountIds.length === 0) return;
 
-    const mailboxes = await getMailboxes();
-    const inbox = mailboxes.find((m) => m.role === 'inbox');
-    if (!inbox) return;
+    activeAccountId = await readActiveAccountId();
 
-    const { ids } = await queryEmails(inbox.id, {
-      filter: { notKeyword: '$seen' },
-      limit: 1,
-    });
-    if (ids.length === 0) return;
+    const matched = await identifyAccountFromFcmData(data, accountIds);
+    const accountsToCheck = matched ? [matched] : accountIds;
 
-    const emailId = ids[0];
-    const previouslyNotified = await AsyncStorage.getItem(LAST_NOTIFIED_EMAIL_ID_KEY);
-    if (previouslyNotified === emailId) return;
-
-    const [email] = await getEmails([emailId]);
-    if (!email) return;
-
-    const from = email.from?.[0];
-    const name = from?.name ?? '';
-    const address = from?.email ?? '';
-    const title = name || address || 'New mail';
-    const body = email.subject || '(no subject)';
-    const initials = getEmailInitials(name, address);
-    const bgColorHex = hslToHex(generateEmailAvatarColor(name, address));
-    const faviconDomain = getFaviconDomain(address);
-    const iconUrl = faviconDomain ? getFaviconUrl(faviconDomain) : undefined;
-
-    const native = NativeModules.BulwarkFcm as BulwarkFcmNative | undefined;
-    if (!native?.showNotification) return;
-
-    await native.showNotification({
-      notificationId: `mail:${emailId}`,
-      title,
-      body,
-      initials,
-      bgColorHex,
-      iconUrl,
-      emailId,
-      threadId: email.threadId,
-      subject: email.subject ?? undefined,
-    });
-
-    await AsyncStorage.setItem(LAST_NOTIFIED_EMAIL_ID_KEY, emailId);
+    for (const accountId of accountsToCheck) {
+      try {
+        await processAccountForPush(accountId);
+      } catch (err) {
+        console.warn(
+          '[push] background check failed for account',
+          accountId,
+          err instanceof Error ? err.message : err,
+        );
+      }
+    }
   } catch (error) {
     console.warn(
       '[push] background task failed:',
       error instanceof Error ? error.message : error,
     );
+  } finally {
+    // Leave the singleton bound to the user's active account so the UI sees
+    // a consistent jmapClient state when the app resumes. Without this, the
+    // last account processed above would remain loaded and the UI's cached
+    // email-store data would not match what the next JMAP request returns.
+    if (activeAccountId) {
+      await jmapClient.loadAccount(activeAccountId).catch(() => undefined);
+    }
   }
 }
 
+async function processAccountForPush(accountId: string): Promise<void> {
+  const loaded = await jmapClient.loadAccount(accountId);
+  if (!loaded) return;
+
+  const mailboxes = await getMailboxes();
+  const inbox = mailboxes.find((m) => m.role === 'inbox');
+  if (!inbox) return;
+
+  const { ids } = await queryEmails(inbox.id, {
+    filter: { notKeyword: '$seen' },
+    limit: 1,
+  });
+  if (ids.length === 0) return;
+
+  const emailId = ids[0];
+  const lastKey = lastNotifiedKey(accountId);
+  const previouslyNotified = await AsyncStorage.getItem(lastKey);
+  if (previouslyNotified === emailId) return;
+
+  const [email] = await getEmails([emailId]);
+  if (!email) return;
+
+  const from = email.from?.[0];
+  const name = from?.name ?? '';
+  const address = from?.email ?? '';
+  const title = name || address || 'New mail';
+  const body = email.subject || '(no subject)';
+  const initials = getEmailInitials(name, address);
+  const bgColorHex = hslToHex(generateEmailAvatarColor(name, address));
+  const faviconDomain = getFaviconDomain(address);
+  const iconUrl = faviconDomain ? getFaviconUrl(faviconDomain) : undefined;
+
+  const native = NativeModules.BulwarkFcm as BulwarkFcmNative | undefined;
+  if (!native?.showNotification) return;
+
+  await native.showNotification({
+    notificationId: `mail:${emailId}`,
+    title,
+    body,
+    initials,
+    bgColorHex,
+    iconUrl,
+    emailId,
+    threadId: email.threadId,
+    subject: email.subject ?? undefined,
+    accountId,
+  });
+
+  await AsyncStorage.setItem(lastKey, emailId);
+}
+
 function hslToHex(hsl: string): string {
   const match = hsl.match(/hsl\(\s*(\d+)\s*,\s*(\d+)%\s*,\s*(\d+)%\s*\)/);
   if (!match) return '#2563eb';

src/lib/push-notifications.ts

@@ -11,12 +11,88 @@ import { jmapClient } from '../api/jmap-client';
 import { generateAccountId } from './account-utils';
 
 // Persist identifiers across launches so we reuse the same JMAP subscription
-// after app restarts. deviceClientId also routes to the relay slot.
-const DEVICE_CLIENT_ID_KEY = 'push:deviceClientId:v1';
-const SUBSCRIPTION_ID_KEY = 'push:subscriptionId:v1';
+// after app restarts. Each account gets its own deviceClientId so the hosted
+// relay can distinguish per-account pushes via the URL slot it forwards.
 const RELAY_BASE_URL_KEY = 'push:relayBaseUrl:v1';
-const PUSH_ACCOUNT_ID_KEY = 'push:accountId:v1';
-const LAST_NOTIFIED_EMAIL_ID_KEY = 'push:lastNotifiedEmailId:v1';
+const PUSH_ACCOUNT_IDS_KEY = 'push:accountIds:v1';
+const DEVICE_CLIENT_ID_PREFIX = 'push:deviceClientId:v2:';
+const SUBSCRIPTION_ID_PREFIX = 'push:subscriptionId:v2:';
+export const LAST_NOTIFIED_EMAIL_ID_PREFIX = 'push:lastNotifiedEmailId:v2:';
+
+// Legacy single-account keys (pre-multi-account). Migrated lazily on the next
+// setupPushNotifications / pushBackgroundTask call, then deleted.
+const LEGACY_DEVICE_CLIENT_ID_KEY = 'push:deviceClientId:v1';
+const LEGACY_SUBSCRIPTION_ID_KEY = 'push:subscriptionId:v1';
+const LEGACY_PUSH_ACCOUNT_ID_KEY = 'push:accountId:v1';
+const LEGACY_LAST_NOTIFIED_EMAIL_ID_KEY = 'push:lastNotifiedEmailId:v1';
+
+export function deviceClientIdKey(accountId: string): string {
+  return DEVICE_CLIENT_ID_PREFIX + accountId;
+}
+
+function subscriptionIdKey(accountId: string): string {
+  return SUBSCRIPTION_ID_PREFIX + accountId;
+}
+
+export function lastNotifiedKey(accountId: string): string {
+  return LAST_NOTIFIED_EMAIL_ID_PREFIX + accountId;
+}
+
+export async function readPushAccountIds(): Promise<string[]> {
+  const raw = await AsyncStorage.getItem(PUSH_ACCOUNT_IDS_KEY);
+  if (!raw) return [];
+  try {
+    const parsed = JSON.parse(raw);
+    if (!Array.isArray(parsed)) return [];
+    return parsed.filter((s): s is string => typeof s === 'string');
+  } catch {
+    return [];
+  }
+}
+
+async function writePushAccountIds(ids: string[]): Promise<void> {
+  const deduped = Array.from(new Set(ids));
+  if (deduped.length === 0) {
+    await AsyncStorage.removeItem(PUSH_ACCOUNT_IDS_KEY);
+  } else {
+    await AsyncStorage.setItem(PUSH_ACCOUNT_IDS_KEY, JSON.stringify(deduped));
+  }
+}
+
+// One-shot migration from the pre-multi-account schema. If the legacy
+// PUSH_ACCOUNT_ID_KEY exists, treat that account as the only pre-existing
+// setup: reuse the legacy deviceClientId and JMAP subscription id under
+// the new per-account keys so the user doesn't lose push on upgrade.
+export async function migrateLegacyPushKeys(): Promise<void> {
+  const legacyAccountId = await AsyncStorage.getItem(LEGACY_PUSH_ACCOUNT_ID_KEY);
+  if (!legacyAccountId) return;
+
+  const legacyDcid = await AsyncStorage.getItem(LEGACY_DEVICE_CLIENT_ID_KEY);
+  const legacySubId = await AsyncStorage.getItem(LEGACY_SUBSCRIPTION_ID_KEY);
+  const legacyLastId = await AsyncStorage.getItem(LEGACY_LAST_NOTIFIED_EMAIL_ID_KEY);
+
+  if (legacyDcid) {
+    await AsyncStorage.setItem(deviceClientIdKey(legacyAccountId), legacyDcid);
+  }
+  if (legacySubId) {
+    await AsyncStorage.setItem(subscriptionIdKey(legacyAccountId), legacySubId);
+  }
+  if (legacyLastId) {
+    await AsyncStorage.setItem(lastNotifiedKey(legacyAccountId), legacyLastId);
+  }
+
+  const ids = await readPushAccountIds();
+  if (!ids.includes(legacyAccountId)) {
+    await writePushAccountIds([...ids, legacyAccountId]);
+  }
+
+  await AsyncStorage.multiRemove([
+    LEGACY_PUSH_ACCOUNT_ID_KEY,
+    LEGACY_DEVICE_CLIENT_ID_KEY,
+    LEGACY_SUBSCRIPTION_ID_KEY,
+    LEGACY_LAST_NOTIFIED_EMAIL_ID_KEY,
+  ]);
+}
 
 // Hosted relay so users don't need to run their own Firebase project. The
 // relay only ever sees FCM tokens + JMAP state-id hashes - no mail content.
@@ -72,11 +148,12 @@ function randomClientId(): string {
   return Array.from(bytes, (b) => b.toString(16).padStart(2, '0')).join('');
 }
 
-async function getOrCreateDeviceClientId(): Promise<string> {
-  const existing = await AsyncStorage.getItem(DEVICE_CLIENT_ID_KEY);
+async function getOrCreateDeviceClientId(accountId: string): Promise<string> {
+  const key = deviceClientIdKey(accountId);
+  const existing = await AsyncStorage.getItem(key);
   if (existing) return existing;
   const next = randomClientId();
-  await AsyncStorage.setItem(DEVICE_CLIENT_ID_KEY, next);
+  await AsyncStorage.setItem(key, next);
   return next;
 }
 
@@ -184,20 +261,24 @@ export async function setupPushNotifications(
   const fcmToken = await native.getToken();
   if (!fcmToken) throw new Error('FCM token unavailable');
 
-  const deviceClientId = await getOrCreateDeviceClientId();
-  await setStoredRelayBaseUrl(relayBaseUrl);
-
-  // Persist the account id so the background push task can reload credentials
-  // from SecureStore without the main app being running.
+  // setupPushNotifications operates on the currently-loaded jmapClient. We
+  // need its username/serverUrl up-front so we can key per-account state.
   const username = jmapClient.username;
   const serverUrl = jmapClient.serverUrl;
-  if (username && serverUrl) {
-    await AsyncStorage.setItem(
-      PUSH_ACCOUNT_ID_KEY,
-      generateAccountId(username, serverUrl),
-    );
+  if (!username || !serverUrl) {
+    throw new Error('No account loaded - cannot set up push');
   }
+  const accountId = generateAccountId(username, serverUrl);
 
+  await migrateLegacyPushKeys();
+
+  const deviceClientId = await getOrCreateDeviceClientId(accountId);
+  await setStoredRelayBaseUrl(relayBaseUrl);
+
+  // Register this account's device-client-id with the relay. Multiple
+  // accounts on the same device end up as separate registrations sharing
+  // one fcmToken - the relay forwards each push individually so the headless
+  // task can identify the source account via the FCM data payload.
   await registerWithRelay({
     relayBaseUrl,
     subscriptionId: deviceClientId,
@@ -208,26 +289,31 @@ export async function setupPushNotifications(
   // Reuse the previous JMAP subscription when the server still has it, but
   // push the expiry forward so it doesn't time out before the next app start.
   const existingSubs = await listPushSubscriptions().catch(() => []);
-  const storedServerId = await AsyncStorage.getItem(SUBSCRIPTION_ID_KEY);
+  const subKey = subscriptionIdKey(accountId);
+  const storedServerId = await AsyncStorage.getItem(subKey);
   if (storedServerId) {
     const match = existingSubs.find((s) => s.id === storedServerId);
     if (match) {
       const refreshed = await refreshSubscriptionExpires(match);
       if (refreshed) {
+        await addPushAccountId(accountId);
         return { subscriptionId: storedServerId, verified: true };
       }
       // Server rejected the refresh (likely the subscription was already
       // deleted server-side) - drop the stale id and recreate below.
       await destroyPushSubscription(storedServerId).catch(() => undefined);
     }
-    await AsyncStorage.removeItem(SUBSCRIPTION_ID_KEY);
+    await AsyncStorage.removeItem(subKey);
   }
 
-  // Reap any leftover Stalwart subscriptions still bound to this device.
-  // These pile up when a previous enable attempt failed mid-flow (verify
-  // race, network blip, app killed). Stalwart per-account rate-limits
-  // PushVerification posts, so leaving stragglers around blocks the new
-  // one's verification - the symptom is a confusing "code does not match".
+  // Reap any leftover Stalwart subscriptions still bound to this account's
+  // deviceClientId. These pile up when a previous enable attempt failed
+  // mid-flow (verify race, network blip, app killed). Stalwart per-account
+  // rate-limits PushVerification posts, so leaving stragglers around blocks
+  // the new one's verification - the symptom is a confusing "code does not
+  // match". Only reap matches for THIS account's deviceClientId; other
+  // accounts' subscriptions on this server (rare but possible if the same
+  // JMAP server backs multiple accounts) must be left alone.
   const stragglers = existingSubs.filter(
     (s) => s.deviceClientId === deviceClientId && s.id !== storedServerId,
   );
@@ -245,11 +331,19 @@ export async function setupPushNotifications(
   const verificationCode = await pollVerificationCode(relayBaseUrl, deviceClientId);
   await verifyPushSubscription(serverAssignedId, verificationCode);
 
-  await AsyncStorage.setItem(SUBSCRIPTION_ID_KEY, serverAssignedId);
+  await AsyncStorage.setItem(subKey, serverAssignedId);
+  await addPushAccountId(accountId);
 
   return { subscriptionId: serverAssignedId, verified: true };
 }
 
+async function addPushAccountId(accountId: string): Promise<void> {
+  const ids = await readPushAccountIds();
+  if (!ids.includes(accountId)) {
+    await writePushAccountIds([...ids, accountId]);
+  }
+}
+
 // Push the subscription's expires forward when it's getting close to the
 // server's ceiling. Returns false if the server rejects the update, which the
 // caller treats as "recreate".
@@ -273,28 +367,92 @@ async function refreshSubscriptionExpires(
   }
 }
 
+async function deregisterFromRelay(
+  relayBaseUrl: string,
+  deviceClientId: string,
+): Promise<void> {
+  await fetch(
+    buildRelayUrl(relayBaseUrl, `/api/push/register/${encodeURIComponent(deviceClientId)}`),
+    { method: 'DELETE' },
+  ).catch(() => undefined);
+}
+
 /**
- * Tear down push on logout / disable. Removes the server-side JMAP
- * subscription, tells the relay to drop the mapping, and clears the local
- * FCM token. Never throws - callers treat teardown as best effort.
+ * Tear down push for a single account. Destroys that account's JMAP
+ * subscription (assumes the jmapClient is currently authenticated to that
+ * account; the active-account logout flow guarantees this) and tells the
+ * relay to drop its mapping. Other accounts' push setups are untouched.
+ *
+ * If no accounts have push left after removal, also deletes the FCM token
+ * so the device stops receiving FCM messages entirely. Never throws -
+ * callers treat teardown as best effort.
+ */
+export async function teardownPushNotificationsForAccount(
+  accountId: string,
+): Promise<void> {
+  await migrateLegacyPushKeys();
+
+  const subKey = subscriptionIdKey(accountId);
+  const storedSubId = await AsyncStorage.getItem(subKey);
+  const dcidKey = deviceClientIdKey(accountId);
+  const storedDcid = await AsyncStorage.getItem(dcidKey);
+  const relayBaseUrl = await getStoredRelayBaseUrl();
+
+  if (storedSubId) {
+    await destroyPushSubscription(storedSubId).catch(() => undefined);
+  }
+  if (relayBaseUrl && storedDcid) {
+    await deregisterFromRelay(relayBaseUrl, storedDcid);
+  }
+
+  await AsyncStorage.multiRemove([subKey, dcidKey, lastNotifiedKey(accountId)]);
+
+  const remaining = (await readPushAccountIds()).filter((id) => id !== accountId);
+  await writePushAccountIds(remaining);
+
+  // If this was the last account with push, kill the FCM token so the device
+  // truly goes silent. Otherwise the token stays alive so the remaining
+  // accounts keep receiving pushes.
+  if (remaining.length === 0) {
+    const native = getNative();
+    if (native) {
+      await native.deleteToken().catch(() => undefined);
+    }
+  }
+}
+
+/**
+ * Tear down push for ALL accounts on this device. Used by the logout-all
+ * flow; best-effort because we typically aren't authenticated to every
+ * account's JMAP server at the moment we need to call destroy on it. The
+ * FCM token is always deleted so no push gets through regardless.
  */
 export async function teardownPushNotifications(): Promise<void> {
-  const storedId = await AsyncStorage.getItem(SUBSCRIPTION_ID_KEY);
-  const relayBaseUrl = await getStoredRelayBaseUrl();
-  const deviceClientId = await AsyncStorage.getItem(DEVICE_CLIENT_ID_KEY);
+  await migrateLegacyPushKeys();
 
-  if (storedId) {
-    await destroyPushSubscription(storedId).catch(() => undefined);
-    await AsyncStorage.removeItem(SUBSCRIPTION_ID_KEY);
+  const accountIds = await readPushAccountIds();
+  const relayBaseUrl = await getStoredRelayBaseUrl();
+
+  for (const accountId of accountIds) {
+    const subKey = subscriptionIdKey(accountId);
+    const dcidKey = deviceClientIdKey(accountId);
+    const storedSubId = await AsyncStorage.getItem(subKey);
+    const storedDcid = await AsyncStorage.getItem(dcidKey);
+
+    if (storedSubId) {
+      // Will only succeed if the jmapClient happens to be authenticated to
+      // this account right now. We don't switch the client to attempt each
+      // one; the subscription will expire server-side instead (90-day TTL).
+      await destroyPushSubscription(storedSubId).catch(() => undefined);
+    }
+    if (relayBaseUrl && storedDcid) {
+      await deregisterFromRelay(relayBaseUrl, storedDcid);
+    }
+    await AsyncStorage.multiRemove([subKey, dcidKey, lastNotifiedKey(accountId)]);
   }
-  if (relayBaseUrl && deviceClientId) {
-    await fetch(
-      buildRelayUrl(relayBaseUrl, `/api/push/register/${encodeURIComponent(deviceClientId)}`),
-      { method: 'DELETE' },
-    ).catch(() => undefined);
-  }
-  await AsyncStorage.removeItem(PUSH_ACCOUNT_ID_KEY);
-  await AsyncStorage.removeItem(LAST_NOTIFIED_EMAIL_ID_KEY);
+
+  await AsyncStorage.removeItem(PUSH_ACCOUNT_IDS_KEY);
+
   const native = getNative();
   if (native) {
     await native.deleteToken().catch(() => undefined);
@@ -327,6 +485,10 @@ export interface NotificationTapPayload {
   emailId: string;
   threadId: string;
   subject?: string;
+  // Identifies which logged-in account the notification was generated for.
+  // Optional for back-compat: older notifications already on the system tray
+  // won't carry this and will fall back to the active account on tap.
+  accountId?: string;
 }
 
 // Returns - and clears - any pending "notification tap" that launched the app

src/lib/sha256.ts

@@ -0,0 +1,131 @@
+// Minimal SHA-256 implementation. Used to verify APK update downloads against
+// the checksum published in the GitHub release body — the JS runtime has no
+// built-in `crypto.subtle.digest` and we don't currently depend on
+// `expo-crypto`. Public-domain algorithm (FIPS 180-4); typical sub-second per
+// MB on a modern phone, which is fine for the rare update flow.
+
+const K = new Uint32Array([
+  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+  0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+  0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+  0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+  0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+  0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+  0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+  0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+]);
+
+function rotr(x: number, n: number): number {
+  return (x >>> n) | (x << (32 - n));
+}
+
+export class Sha256 {
+  private h = new Uint32Array([
+    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
+    0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
+  ]);
+  private buffer = new Uint8Array(64);
+  private bufferLen = 0;
+  private byteCount = 0;
+
+  update(bytes: Uint8Array): void {
+    let i = 0;
+    this.byteCount += bytes.length;
+    while (i < bytes.length) {
+      const room = 64 - this.bufferLen;
+      const chunk = Math.min(room, bytes.length - i);
+      this.buffer.set(bytes.subarray(i, i + chunk), this.bufferLen);
+      this.bufferLen += chunk;
+      i += chunk;
+      if (this.bufferLen === 64) {
+        this.process(this.buffer);
+        this.bufferLen = 0;
+      }
+    }
+  }
+
+  digestHex(): string {
+    // Final block: append 0x80, pad with zeros, then 8-byte big-endian length.
+    const totalBits = this.byteCount * 8;
+    this.buffer[this.bufferLen++] = 0x80;
+    if (this.bufferLen > 56) {
+      while (this.bufferLen < 64) this.buffer[this.bufferLen++] = 0;
+      this.process(this.buffer);
+      this.bufferLen = 0;
+    }
+    while (this.bufferLen < 56) this.buffer[this.bufferLen++] = 0;
+    // 64-bit length, big-endian. We can't represent >2^53 - JS bitops are
+    // 32-bit, so split into hi/lo words.
+    const hi = Math.floor(totalBits / 0x100000000);
+    const lo = totalBits >>> 0;
+    this.buffer[56] = (hi >>> 24) & 0xff;
+    this.buffer[57] = (hi >>> 16) & 0xff;
+    this.buffer[58] = (hi >>> 8) & 0xff;
+    this.buffer[59] = hi & 0xff;
+    this.buffer[60] = (lo >>> 24) & 0xff;
+    this.buffer[61] = (lo >>> 16) & 0xff;
+    this.buffer[62] = (lo >>> 8) & 0xff;
+    this.buffer[63] = lo & 0xff;
+    this.process(this.buffer);
+
+    let out = '';
+    for (let i = 0; i < 8; i++) {
+      out += this.h[i].toString(16).padStart(8, '0');
+    }
+    return out;
+  }
+
+  private process(block: Uint8Array): void {
+    const w = new Uint32Array(64);
+    for (let i = 0; i < 16; i++) {
+      w[i] =
+        (block[i * 4] << 24) |
+        (block[i * 4 + 1] << 16) |
+        (block[i * 4 + 2] << 8) |
+        block[i * 4 + 3];
+    }
+    for (let i = 16; i < 64; i++) {
+      const s0 = rotr(w[i - 15], 7) ^ rotr(w[i - 15], 18) ^ (w[i - 15] >>> 3);
+      const s1 = rotr(w[i - 2], 17) ^ rotr(w[i - 2], 19) ^ (w[i - 2] >>> 10);
+      w[i] = (w[i - 16] + s0 + w[i - 7] + s1) | 0;
+    }
+
+    let a = this.h[0], b = this.h[1], c = this.h[2], d = this.h[3];
+    let e = this.h[4], f = this.h[5], g = this.h[6], hh = this.h[7];
+
+    for (let i = 0; i < 64; i++) {
+      const S1 = rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25);
+      const ch = (e & f) ^ (~e & g);
+      const temp1 = (hh + S1 + ch + K[i] + w[i]) | 0;
+      const S0 = rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22);
+      const mj = (a & b) ^ (a & c) ^ (b & c);
+      const temp2 = (S0 + mj) | 0;
+      hh = g;
+      g = f;
+      f = e;
+      e = (d + temp1) | 0;
+      d = c;
+      c = b;
+      b = a;
+      a = (temp1 + temp2) | 0;
+    }
+
+    this.h[0] = (this.h[0] + a) | 0;
+    this.h[1] = (this.h[1] + b) | 0;
+    this.h[2] = (this.h[2] + c) | 0;
+    this.h[3] = (this.h[3] + d) | 0;
+    this.h[4] = (this.h[4] + e) | 0;
+    this.h[5] = (this.h[5] + f) | 0;
+    this.h[6] = (this.h[6] + g) | 0;
+    this.h[7] = (this.h[7] + hh) | 0;
+  }
+}
+
+export function sha256Hex(bytes: Uint8Array): string {
+  const h = new Sha256();
+  h.update(bytes);
+  return h.digestHex();
+}

src/screens/LoginScreen.tsx

@@ -1,12 +1,15 @@
 import React from 'react';
 import { View, Text, Pressable, StyleSheet, KeyboardAvoidingView, Platform, Image } from 'react-native';
 import { SafeAreaView } from 'react-native-safe-area-context';
+import Constants from 'expo-constants';
 import { Eye, EyeOff, X } from 'lucide-react-native';
 import { spacing, radius, typography, componentSizes, type ThemePalette } from '../theme/tokens';
 import { useColors } from '../theme/colors';
 import { Button, Input } from '../components';
 import { useAuthStore } from '../stores/auth-store';
 
+const APP_VERSION = Constants.expoConfig?.version ?? '0.0.0';
+
 interface LoginScreenProps {
   onLogin?: () => void;
   isAddMode?: boolean;
@@ -156,7 +159,7 @@ export default function LoginScreen({ onLogin, isAddMode, onCancel }: LoginScree
 
           {/* Footer */}
           <View style={styles.footer}>
-            <Text style={styles.footerText}>Bulwark Mobile v0.0.1</Text>
+            <Text style={styles.footerText}>Bulwark Mobile v{APP_VERSION}</Text>
             <Text style={styles.footerLink}>Privacy Policy</Text>
           </View>
         </View>

src/screens/SettingsScreen.tsx

@@ -210,14 +210,20 @@ export default function SettingsScreen({ onLogout, onBack, onTabSelect }: Settin
 
   return (
     <SafeAreaView style={styles.container} edges={['top']}>
-      {/* Header - matches webmail mobile: h-14, border-b, back button + icon + title */}
+      {/* Header - matches webmail mobile: h-14, border-b, back button + icon + title.
+          Settings is a tab root, so the back button is only rendered when a
+          parent passes onBack (it'd otherwise lead nowhere). */}
       <View style={styles.header}>
-        <Pressable
-          onPress={onBack}
-          style={({ pressed }) => [styles.headerBackBtn, pressed && styles.headerBackBtnPressed]}
-        >
-          <ArrowLeft size={20} color={c.text} />
-        </Pressable>
+        {onBack ? (
+          <Pressable
+            onPress={onBack}
+            style={({ pressed }) => [styles.headerBackBtn, pressed && styles.headerBackBtnPressed]}
+          >
+            <ArrowLeft size={20} color={c.text} />
+          </Pressable>
+        ) : (
+          <View style={styles.headerLeftSpacer} />
+        )}
         <Settings size={20} color={c.mutedForeground} />
         <Text style={styles.headerTitle}>{t('settings.title', 'Settings')}</Text>
       </View>
@@ -310,6 +316,7 @@ function makeStyles(c: ThemePalette) {
       borderRadius: radius.md,
     },
     headerBackBtnPressed: { backgroundColor: c.accent },
+    headerLeftSpacer: { width: spacing.sm },
     headerTitle: { ...typography.h3, color: c.text },
 
     scrollArea: { flex: 1 },

src/stores/__tests__/auth-store.test.ts

@@ -1,42 +1,63 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 
-vi.mock('expo-secure-store', () => ({
-  setItemAsync: vi.fn(),
-  getItemAsync: vi.fn(),
-  deleteItemAsync: vi.fn(),
-}));
-
 vi.mock('../../api/jmap-client', () => ({
   jmapClient: {
     connect: vi.fn(),
     logout: vi.fn(),
     restoreSession: vi.fn(),
+    loadAccount: vi.fn(),
+    consumeLegacyCredentials: vi.fn(async () => null),
+    clearAccountCredentials: vi.fn(async () => undefined),
+    clearAllCredentials: vi.fn(async () => undefined),
+    reset: vi.fn(),
     accountId: 'acc-1',
     currentSession: { apiUrl: 'https://mail.example.com/jmap/' },
+    username: 'user',
+    serverUrl: 'https://mail.example.com',
   },
   AuthenticationError: class AuthenticationError extends Error {
     constructor(msg: string) { super(msg); this.name = 'AuthenticationError'; }
   },
+  NetworkError: class NetworkError extends Error {
+    constructor(msg: string) { super(msg); this.name = 'NetworkError'; }
+  },
+}));
+
+vi.mock('../../lib/push-notifications', () => ({
+  teardownPushNotifications: vi.fn(async () => undefined),
+  teardownPushNotificationsForAccount: vi.fn(async () => undefined),
 }));
 
 import { jmapClient } from '../../api/jmap-client';
 import { useAuthStore } from '../auth-store';
+import { useAccountStore } from '../account-store';
 
 const mockConnect = jmapClient.connect as ReturnType<typeof vi.fn>;
 const mockLogout = jmapClient.logout as ReturnType<typeof vi.fn>;
-const mockRestore = jmapClient.restoreSession as ReturnType<typeof vi.fn>;
+const mockLoadAccount = jmapClient.loadAccount as ReturnType<typeof vi.fn>;
+
+function resetAccountStore(): void {
+  useAccountStore.setState({
+    accounts: [],
+    activeAccountId: null,
+    defaultAccountId: null,
+  });
+}
 
 beforeEach(() => {
   vi.clearAllMocks();
-  // Reset store state
+  resetAccountStore();
   useAuthStore.setState({
     isAuthenticated: false,
     isLoading: false,
+    hasRestoredSession: false,
     error: null,
     serverUrl: null,
     username: null,
     session: null,
     accountId: null,
+    activeAccountId: null,
+    client: null,
   });
 });
 
@@ -83,7 +104,7 @@ describe('auth-store', () => {
   });
 
   describe('logout', () => {
-    it('should reset all state', async () => {
+    it('should reset all state when no other accounts remain', async () => {
       useAuthStore.setState({ isAuthenticated: true, serverUrl: 'x', username: 'y' });
       mockLogout.mockResolvedValue(undefined);
 
@@ -97,23 +118,40 @@ describe('auth-store', () => {
   });
 
   describe('restoreSession', () => {
-    it('should restore on success', async () => {
-      mockRestore.mockResolvedValue(true);
+    it('should return false when there is no registered account', async () => {
+      const restored = await useAuthStore.getState().restoreSession();
+
+      expect(restored).toBe(false);
+      expect(useAuthStore.getState().isAuthenticated).toBe(false);
+      expect(useAuthStore.getState().hasRestoredSession).toBe(true);
+    });
+
+    it('should restore when loadAccount succeeds for the active account', async () => {
+      useAccountStore.setState({
+        accounts: [
+          {
+            id: 'acc-1',
+            serverUrl: 'https://mail.example.com',
+            username: 'user',
+            displayName: 'user',
+            email: 'user',
+            avatarColor: '#000',
+            lastLoginAt: 0,
+            isConnected: false,
+            hasError: false,
+            isDefault: true,
+          },
+        ],
+        activeAccountId: 'acc-1',
+        defaultAccountId: 'acc-1',
+      });
+      mockLoadAccount.mockResolvedValue(true);
 
       const restored = await useAuthStore.getState().restoreSession();
 
       expect(restored).toBe(true);
       expect(useAuthStore.getState().isAuthenticated).toBe(true);
     });
-
-    it('should return false when no session to restore', async () => {
-      mockRestore.mockResolvedValue(false);
-
-      const restored = await useAuthStore.getState().restoreSession();
-
-      expect(restored).toBe(false);
-      expect(useAuthStore.getState().isAuthenticated).toBe(false);
-    });
   });
 
   describe('clearError', () => {

src/stores/auth-store.ts

@@ -6,7 +6,10 @@ import { useEmailStore } from './email-store';
 import { useContactsStore } from './contacts-store';
 import { useCalendarStore } from './calendar-store';
 import { generateAccountId } from '../lib/account-utils';
-import { teardownPushNotifications } from '../lib/push-notifications';
+import {
+  teardownPushNotifications,
+  teardownPushNotificationsForAccount,
+} from '../lib/push-notifications';
 
 // Persist middleware hydrates asynchronously on cold start. Without this
 // guard, restoreSession() can read the account-store before AsyncStorage has
@@ -143,9 +146,14 @@ export const useAuthStore = create<AuthState>((set, get) => ({
     const accountStore = useAccountStore.getState();
     const currentId = get().activeAccountId;
 
-    // Best-effort: revoke the JMAP PushSubscription and drop the relay
-    // mapping before we lose credentials. Do not abort logout on failure.
-    await teardownPushNotifications().catch(() => undefined);
+    // Best-effort: revoke this account's JMAP PushSubscription and drop its
+    // relay mapping before we lose credentials. Other logged-in accounts'
+    // push setups remain untouched. Do not abort logout on failure.
+    if (currentId) {
+      await teardownPushNotificationsForAccount(currentId).catch(() => undefined);
+    } else {
+      await teardownPushNotifications().catch(() => undefined);
+    }
 
     // Clear credentials for this account first
     if (currentId) {

src/stores/email-store.ts

@@ -1,7 +1,8 @@
 import { create } from 'zustand';
 import { persist, createJSONStorage } from 'zustand/middleware';
 import AsyncStorage from '@react-native-async-storage/async-storage';
-import type { Email, Mailbox } from '../api/types';
+import type { Email, Mailbox, StateChange } from '../api/types';
+import { jmapClient } from '../api/jmap-client';
 import {
   getMailboxes as fetchMailboxes,
   queryEmails,
@@ -57,6 +58,7 @@ export interface EmailState {
   selectMailbox: (mailboxId: string) => Promise<void>;
   loadMoreEmails: () => Promise<void>;
   refreshEmails: () => Promise<void>;
+  handleStateChange: (change: StateChange) => Promise<void>;
   getEmailDetail: (id: string) => Promise<Email>;
   markRead: (emailId: string) => Promise<void>;
   markUnread: (emailId: string) => Promise<void>;
@@ -150,15 +152,43 @@ export const useEmailStore = create<EmailState>()(
       filters: {},
       pendingUndo: null,
     });
+
+    // Seed from the offline cache immediately so changing folders shows
+    // something even before the network responds — and is the fallback
+    // when offline. The network result will replace this once it arrives.
+    const cacheStore = useOfflineCacheStore.getState();
+    if (!cacheStore.hydrated) await cacheStore.hydrate();
+    const limit = useSettingsStore.getState().emailsPerPage;
+    let cached: Email[] = [];
+    if (cacheStore.totalCount() > 0) {
+      try {
+        cached = await cacheStore.getEmailsInMailbox(mailboxId, Math.max(limit, 50));
+        if (cached.length > 0 && get().currentMailboxId === mailboxId) {
+          set({ emails: cached, totalEmails: cached.length });
+        }
+      } catch (err) {
+        console.warn('[email-store] cache seed failed:', err);
+      }
+    }
+
     try {
       const filter = buildJmapFilter(mailboxId, '', {});
-      const limit = useSettingsStore.getState().emailsPerPage;
       const { ids, total } = await queryEmails(mailboxId, { limit, filter });
       const emails = ids.length > 0 ? await fetchEmails(ids) : [];
+      // Race guard: don't overwrite if the user already moved to a different
+      // mailbox while this request was in flight.
+      if (get().currentMailboxId !== mailboxId) return;
       set({ emails, totalEmails: total, loading: false });
     } catch (err) {
       console.warn('[email-store] selectMailbox failed:', err);
-      set({ loading: false, error: err instanceof Error ? err.message : 'Failed to load emails' });
+      if (get().currentMailboxId !== mailboxId) return;
+      // Keep whatever the cache seeded with; only surface the error when the
+      // cache is empty. With cached emails visible the OfflineBanner already
+      // tells the user the data is stale.
+      set({
+        loading: false,
+        error: cached.length > 0 ? null : (err instanceof Error ? err.message : 'Failed to load emails'),
+      });
     }
   },
 
@@ -183,7 +213,7 @@ export const useEmailStore = create<EmailState>()(
   },
 
   refreshEmails: async () => {
-    const { currentMailboxId, searchQuery, filters } = get();
+    const { currentMailboxId, searchQuery, filters, emails: existing } = get();
     if (!currentMailboxId) return;
     // Keep existing emails visible while refreshing - swap atomically once
     // the new list is ready so pull-to-refresh doesn't flash an empty list.
@@ -196,10 +226,50 @@ export const useEmailStore = create<EmailState>()(
       set({ emails, totalEmails: total, loading: false });
     } catch (err) {
       console.warn('[email-store] refreshEmails failed:', err);
+      // If the list was empty before the refresh attempt, fall back to the
+      // offline cache so the user still sees something. Otherwise keep what
+      // they had visible and let the OfflineBanner explain.
+      if (existing.length === 0) {
+        try {
+          const cacheStore = useOfflineCacheStore.getState();
+          if (!cacheStore.hydrated) await cacheStore.hydrate();
+          if (cacheStore.totalCount() > 0) {
+            const limit = useSettingsStore.getState().emailsPerPage;
+            const cached = await cacheStore.getEmailsInMailbox(
+              currentMailboxId,
+              Math.max(limit, 50),
+            );
+            if (get().currentMailboxId === currentMailboxId && cached.length > 0) {
+              set({ emails: cached, totalEmails: cached.length, loading: false, error: null });
+              return;
+            }
+          }
+        } catch (cacheErr) {
+          console.warn('[email-store] refresh cache fallback failed:', cacheErr);
+        }
+      }
       set({ loading: false, error: err instanceof Error ? err.message : 'Failed to load emails' });
     }
   },
 
+  handleStateChange: async (change) => {
+    if (!jmapClient.currentSession) return;
+    const accountId = jmapClient.accountId;
+    const accountChanges = change.changed?.[accountId];
+    if (!accountChanges) return;
+
+    const mailboxChanged = 'Mailbox' in accountChanges;
+    const emailChanged = 'Email' in accountChanges || 'EmailDelivery' in accountChanges;
+    if (!mailboxChanged && !emailChanged) return;
+
+    if (mailboxChanged) {
+      await get().fetchMailboxes();
+    }
+    if (emailChanged && get().currentMailboxId) {
+      await get().refreshEmails();
+    }
+  },
+
   setSearchQuery: (query) => {
     set({ searchQuery: query });
     void get().refreshEmails();

src/stores/offline-cache-store.ts

@@ -59,6 +59,12 @@ interface OfflineCacheState {
   remove: (ids: string[]) => Promise<void>;
   clearAll: () => Promise<void>;
 
+  // Returns cached emails whose `mailboxIds` include the given mailbox,
+  // sorted by `receivedAt` descending. Used by selectMailbox to seed the
+  // list when the network is unavailable. Loads each entry from
+  // AsyncStorage; the index doesn't carry the mailbox set.
+  getEmailsInMailbox: (mailboxId: string, limit?: number) => Promise<Email[]>;
+
   totalSize: () => number;
   totalCount: () => number;
 
@@ -154,6 +160,31 @@ export const useOfflineCacheStore = create<OfflineCacheState>((set, get) => ({
     persistIndex(index);
   },
 
+  getEmailsInMailbox: async (mailboxId, limit = 200) => {
+    // Sort the index by receivedAt descending first so we don't have to read
+    // entries we won't return — the index already carries receivedAt.
+    const sorted = Object.values(get().index.entries).sort((a, b) => {
+      const at = a.receivedAt ? new Date(a.receivedAt).getTime() : 0;
+      const bt = b.receivedAt ? new Date(b.receivedAt).getTime() : 0;
+      return bt - at;
+    });
+    const matches: Email[] = [];
+    for (const entry of sorted) {
+      if (matches.length >= limit) break;
+      try {
+        const raw = await AsyncStorage.getItem(entryKey(entry.id));
+        if (!raw) continue;
+        const email = JSON.parse(raw) as Email;
+        if (email.mailboxIds?.[mailboxId]) {
+          matches.push(email);
+        }
+      } catch {
+        // skip corrupt entries — they'll be replaced on next sync
+      }
+    }
+    return matches;
+  },
+
   totalSize: () => {
     let n = 0;
     for (const e of Object.values(get().index.entries)) n += e.size;

src/stores/settings-store.ts

@@ -133,12 +133,11 @@ interface PersistedSettings {
   pluginEnabled: Record<string, boolean>;
 
   // Offline mail cache: download recent message bodies in the background so
-  // they can be opened without network. Days windows the lookback; the
-  // attachments toggle controls whether file blobs are cached too (off by
-  // default — bodies-only is much smaller).
+  // they can be opened without network. Days windows the lookback. Attachment
+  // caching is intentionally not implemented yet — bodies-only is much
+  // smaller and covers the "open recent mail offline" UX on its own.
   offlineCacheEnabled: boolean;
   offlineCacheDays: number;
-  offlineCacheIncludeAttachments: boolean;
 }
 
 const DEFAULT_PERSISTED: PersistedSettings = {
@@ -218,7 +217,6 @@ const DEFAULT_PERSISTED: PersistedSettings = {
 
   offlineCacheEnabled: false,
   offlineCacheDays: 7,
-  offlineCacheIncludeAttachments: false,
 };
 
 export interface SettingsState extends PersistedSettings {

src/stores/updates-store.ts

@@ -108,9 +108,15 @@ export const useUpdatesStore = create<UpdatesState>((set, get) => ({
     if (s.installing || !s.cachedLatest?.apkAsset) return;
     set({ installing: true, error: null, installProgress: { phase: 'downloading', progress: 0 } });
     try {
-      await downloadAndInstallApk(s.cachedLatest.apkAsset, (p) => {
-        set({ installProgress: p });
-      });
+      await downloadAndInstallApk(
+        {
+          asset: s.cachedLatest.apkAsset,
+          expectedSha256: s.cachedLatest.apkSha256,
+        },
+        (p) => {
+          set({ installProgress: p });
+        },
+      );
       set({ installing: false, installProgress: null });
     } catch (err) {
       set({

src/test-setup.ts

@@ -0,0 +1,66 @@
+// Vitest setup. Two pieces of plumbing the unit tests need:
+//
+// 1. AsyncStorage: the Zustand `persist` middleware used by several stores
+//    reaches in during `set()` calls, which on a `node` environment crashes
+//    inside the RN AsyncStorage shim (no `window` global). Swap in an
+//    in-memory implementation.
+// 2. react-native: the bundled entry point is Flow-typed and rolldown can't
+//    parse it. Stub the few surfaces used at module-load time so any store
+//    that transitively imports `react-native` (via push / client-cert
+//    bridges) loads cleanly. Tests that actually exercise native modules
+//    re-mock the relevant module locally.
+
+import { vi } from 'vitest';
+
+const memory = new Map<string, string>();
+
+vi.mock('@react-native-async-storage/async-storage', () => ({
+  default: {
+    getItem: vi.fn(async (key: string) => memory.get(key) ?? null),
+    setItem: vi.fn(async (key: string, value: string) => {
+      memory.set(key, value);
+    }),
+    removeItem: vi.fn(async (key: string) => {
+      memory.delete(key);
+    }),
+    clear: vi.fn(async () => {
+      memory.clear();
+    }),
+    getAllKeys: vi.fn(async () => Array.from(memory.keys())),
+    multiGet: vi.fn(async (keys: string[]) =>
+      keys.map((k) => [k, memory.get(k) ?? null] as [string, string | null]),
+    ),
+    multiSet: vi.fn(async (pairs: [string, string][]) => {
+      for (const [k, v] of pairs) memory.set(k, v);
+    }),
+    multiRemove: vi.fn(async (keys: string[]) => {
+      for (const k of keys) memory.delete(k);
+    }),
+  },
+}));
+
+vi.mock('react-native', () => {
+  class NativeEventEmitter {
+    addListener() {
+      return { remove: () => undefined };
+    }
+    removeAllListeners() {}
+  }
+  return {
+    Platform: { OS: 'android', Version: 33, select: <T,>(spec: { default?: T; android?: T; ios?: T }) => spec.android ?? spec.default ?? spec.ios },
+    NativeModules: {},
+    NativeEventEmitter,
+    PermissionsAndroid: {
+      RESULTS: { GRANTED: 'granted', DENIED: 'denied', NEVER_ASK_AGAIN: 'never_ask_again' },
+      request: async () => 'granted',
+    },
+    Linking: { openURL: async () => undefined },
+    Appearance: { getColorScheme: () => 'dark', addChangeListener: () => ({ remove: () => undefined }) },
+  };
+});
+
+vi.mock('expo-secure-store', () => ({
+  setItemAsync: vi.fn(async () => undefined),
+  getItemAsync: vi.fn(async () => null),
+  deleteItemAsync: vi.fn(async () => undefined),
+}));

vitest.config.ts

@@ -5,5 +5,6 @@ export default defineConfig({
     globals: true,
     environment: 'node',
     include: ['src/**/__tests__/**/*.test.ts'],
+    setupFiles: ['src/test-setup.ts'],
   },
 });