chore: update version number to 0.1.72

Since releases ship an `.apk.sha256` file, every in-app update checks
the downloaded APK against it. The check read the 40 MB file in base64
chunks and hashed it in JS, which took longer than the download, and it
reset the progress bar to 0 under the "Downloading" label, so the update
looked like it downloaded twice, the second time slowly.

The file is now read and hashed natively through expo-crypto (the JS
hasher remains as a fallback), and the bar stays full under a
"Verifying…" label while the check runs.

VERSION

@@ -1 +1 @@
-0.1.70
+0.1.72

locales/rn/ar.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "تابع تقدّم البناء أو نزّل ملف APK يدويًا.",
     "severity_deprecated": "إلزامي",
     "severity_security": "أمني",
-    "title": "تحديثات التطبيق"
+    "title": "تحديثات التطبيق",
+    "verifying": "جارٍ التحقق…"
   }
 }

locales/rn/ca.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Seguiu el progrés de la compilació o baixeu l'APK manualment.",
     "severity_deprecated": "Obligatòria",
     "severity_security": "Seguretat",
-    "title": "Actualitzacions de l'aplicació"
+    "title": "Actualitzacions de l'aplicació",
+    "verifying": "S'està verificant…"
   }
 }

locales/rn/cs.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Sledujte průběh sestavení nebo si stáhněte APK ručně.",
     "severity_deprecated": "Povinná",
     "severity_security": "Zabezpečení",
-    "title": "Aktualizace aplikace"
+    "title": "Aktualizace aplikace",
+    "verifying": "Ověřování…"
   }
 }

locales/rn/da.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Følg buildets fremskridt, eller download APK'en manuelt.",
     "severity_deprecated": "Påkrævet",
     "severity_security": "Sikkerhed",
-    "title": "Appopdateringer"
+    "title": "Appopdateringer",
+    "verifying": "Verificerer…"
   }
 }

locales/rn/de.json

@@ -1168,7 +1168,8 @@
     "release_page_pending_desc": "Den Build-Fortschritt verfolgen oder die APK manuell herunterladen.",
     "severity_deprecated": "Erforderlich",
     "severity_security": "Sicherheit",
-    "title": "App-Updates"
+    "title": "App-Updates",
+    "verifying": "Wird überprüft…"
   },
   "widgets": {
     "attachments": {

locales/rn/en.json

@@ -1184,7 +1184,8 @@
     "release_page_pending_desc": "Watch the build progress or download the APK manually.",
     "severity_deprecated": "Required",
     "severity_security": "Security",
-    "title": "App updates"
+    "title": "App updates",
+    "verifying": "Verifying…"
   },
   "widgets": {
     "attachments": {

locales/rn/es.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Sigue el progreso de la compilación o descarga el APK manualmente.",
     "severity_deprecated": "Obligatoria",
     "severity_security": "Seguridad",
-    "title": "Actualizaciones de la app"
+    "title": "Actualizaciones de la app",
+    "verifying": "Verificando…"
   }
 }

locales/rn/fa.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "روند ساخت را دنبال کنید یا APK را دستی دانلود کنید.",
     "severity_deprecated": "الزامی",
     "severity_security": "امنیتی",
-    "title": "به‌روزرسانی‌های برنامه"
+    "title": "به‌روزرسانی‌های برنامه",
+    "verifying": "در حال بررسی…"
   }
 }

locales/rn/fr.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Suivez l'avancement de la compilation ou téléchargez l'APK manuellement.",
     "severity_deprecated": "Requise",
     "severity_security": "Sécurité",
-    "title": "Mises à jour de l'application"
+    "title": "Mises à jour de l'application",
+    "verifying": "Vérification…"
   }
 }

locales/rn/he.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "עקוב אחר התקדמות הבנייה או הורד את ה-APK ידנית.",
     "severity_deprecated": "חובה",
     "severity_security": "אבטחה",
-    "title": "עדכוני אפליקציה"
+    "title": "עדכוני אפליקציה",
+    "verifying": "מאמת…"
   }
 }

locales/rn/hu.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Kövesd a build folyamatát, vagy töltsd le kézzel az APK-t.",
     "severity_deprecated": "Kötelező",
     "severity_security": "Biztonsági",
-    "title": "Alkalmazásfrissítések"
+    "title": "Alkalmazásfrissítések",
+    "verifying": "Ellenőrzés…"
   }
 }

locales/rn/it.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Segui l'avanzamento della build o scarica l'APK manualmente.",
     "severity_deprecated": "Obbligatorio",
     "severity_security": "Sicurezza",
-    "title": "Aggiornamenti dell'app"
+    "title": "Aggiornamenti dell'app",
+    "verifying": "Verifica in corso…"
   }
 }

locales/rn/ja.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "ビルドの進行状況を確認するか、APK を手動でダウンロードします。",
     "severity_deprecated": "必須",
     "severity_security": "セキュリティ",
-    "title": "アプリのアップデート"
+    "title": "アプリのアップデート",
+    "verifying": "検証中…"
   }
 }

locales/rn/ko.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "빌드 진행 상황을 확인하거나 APK를 직접 다운로드해요.",
     "severity_deprecated": "필수",
     "severity_security": "보안",
-    "title": "앱 업데이트"
+    "title": "앱 업데이트",
+    "verifying": "확인 중…"
   }
 }

locales/rn/lv.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Sekojiet būvēšanas gaitai vai lejupielādējiet APK manuāli.",
     "severity_deprecated": "Obligāts",
     "severity_security": "Drošība",
-    "title": "Lietotnes atjauninājumi"
+    "title": "Lietotnes atjauninājumi",
+    "verifying": "Pārbauda…"
   }
 }

locales/rn/mn.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Бүтээлтийн явцыг хянах эсвэл APK-г гараар татаж авах.",
     "severity_deprecated": "Заавал",
     "severity_security": "Аюулгүй байдал",
-    "title": "Аппын шинэчлэл"
+    "title": "Аппын шинэчлэл",
+    "verifying": "Шалгаж байна…"
   }
 }

locales/rn/nb.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Følg fremdriften for byggingen, eller last ned APK-filen manuelt.",
     "severity_deprecated": "Påkrevd",
     "severity_security": "Sikkerhet",
-    "title": "Appoppdateringer"
+    "title": "Appoppdateringer",
+    "verifying": "Verifiserer…"
   }
 }

locales/rn/nl.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Volg de voortgang van de build of download de APK handmatig.",
     "severity_deprecated": "Vereist",
     "severity_security": "Beveiliging",
-    "title": "App-updates"
+    "title": "App-updates",
+    "verifying": "Controleren…"
   }
 }

locales/rn/pl.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Śledź postęp budowania lub pobierz plik APK ręcznie.",
     "severity_deprecated": "Wymagana",
     "severity_security": "Bezpieczeństwo",
-    "title": "Aktualizacje aplikacji"
+    "title": "Aktualizacje aplikacji",
+    "verifying": "Weryfikowanie…"
   }
 }

locales/rn/pt.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Acompanhe o progresso da compilação ou baixe o APK manualmente.",
     "severity_deprecated": "Obrigatória",
     "severity_security": "Segurança",
-    "title": "Atualizações do app"
+    "title": "Atualizações do app",
+    "verifying": "Verificando…"
   }
 }

locales/rn/ro.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Urmăriți progresul compilării sau descărcați manual APK-ul.",
     "severity_deprecated": "Obligatorie",
     "severity_security": "Securitate",
-    "title": "Actualizări aplicație"
+    "title": "Actualizări aplicație",
+    "verifying": "Se verifică…"
   }
 }

locales/rn/ru.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Следите за ходом сборки или скачайте APK вручную.",
     "severity_deprecated": "Обязательное",
     "severity_security": "Безопасность",
-    "title": "Обновления приложения"
+    "title": "Обновления приложения",
+    "verifying": "Проверка…"
   }
 }

locales/rn/sk.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Sledujte priebeh zostavenia alebo si stiahnite APK ručne.",
     "severity_deprecated": "Povinná",
     "severity_security": "Zabezpečenie",
-    "title": "Aktualizácie aplikácie"
+    "title": "Aktualizácie aplikácie",
+    "verifying": "Overovanie…"
   }
 }

locales/rn/tr.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Derleme ilerlemesini izleyin veya APK'yı elle indirin.",
     "severity_deprecated": "Zorunlu",
     "severity_security": "Güvenlik",
-    "title": "Uygulama güncellemeleri"
+    "title": "Uygulama güncellemeleri",
+    "verifying": "Doğrulanıyor…"
   }
 }

locales/rn/uk.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "Стежте за перебігом збирання або завантажте APK вручну.",
     "severity_deprecated": "Обов'язкове",
     "severity_security": "Безпека",
-    "title": "Оновлення застосунку"
+    "title": "Оновлення застосунку",
+    "verifying": "Перевірка…"
   }
 }

locales/rn/zh-TW.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "查看建置進度或手動下載 APK。",
     "severity_deprecated": "必要",
     "severity_security": "安全性",
-    "title": "應用程式更新"
+    "title": "應用程式更新",
+    "verifying": "正在驗證…"
   }
 }

locales/rn/zh.json

@@ -1168,6 +1168,7 @@
     "release_page_pending_desc": "查看构建进度或手动下载 APK。",
     "severity_deprecated": "必需",
     "severity_security": "安全",
-    "title": "应用更新"
+    "title": "应用更新",
+    "verifying": "正在验证…"
   }
 }

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.70",
+  "version": "0.1.72",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "bulwark-mobile",
-      "version": "0.1.70",
+      "version": "0.1.72",
       "license": "AGPL-3.0-only",
       "dependencies": {
         "@react-native-async-storage/async-storage": "2.2.0",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.70",
+  "version": "0.1.72",
   "license": "AGPL-3.0-only",
   "main": "index.ts",
   "scripts": {

src/components/EmailBodyView.tsx

@@ -12,7 +12,8 @@ import { bodyDocument } from '../lib/email-body-document';
 import { estimateBodyHeight, lastBodyHeight, rememberBodyHeight } from '../lib/body-heights';
 import { parseMailtoUrl } from '../lib/unsubscribe';
 import { fetchInlineImageDataUri } from '../lib/email-export';
-import { isSenderContentTrusted } from '../lib/trusted-senders';
+import { isSenderContentTrusted, isTrustedSendersSyncOn } from '../lib/trusted-senders';
+import { useHasContacts } from '../lib/capabilities';
 import { useSettingsStore } from '../stores/settings-store';
 import { useContactsStore } from '../stores/contacts-store';
 import { useLocaleStore } from '../stores/locale-store';
@@ -527,6 +528,8 @@ export default function EmailBodyView({
   const isSenderTrusted = useSettingsStore((s) => s.isSenderTrusted);
   const addTrustedSender = useSettingsStore((s) => s.addTrustedSender);
   const trustedSendersAddressBook = useSettingsStore((s) => s.trustedSendersAddressBook);
+  const hasContacts = useHasContacts();
+  const syncTrustedSenders = isTrustedSendersSyncOn(trustedSendersAddressBook, hasContacts);
   const emailAlwaysLightMode = useSettingsStore((s) => s.emailAlwaysLightMode);
   const plainTextFont = useSettingsStore((s) => s.plainTextFont);
   const messageSpacing = useSettingsStore((s) => s.messageSpacing);
@@ -540,8 +543,8 @@ export default function EmailBodyView({
   // entries (synced across devices) feed the external-content trust check. We
   // do not create the book here — it is created lazily when a sender is trusted.
   React.useEffect(() => {
-    if (trustedSendersAddressBook && !trustedSendersLoaded) void loadTrustedSendersBook(false);
-  }, [trustedSendersAddressBook, trustedSendersLoaded, loadTrustedSendersBook]);
+    if (syncTrustedSenders && !trustedSendersLoaded) void loadTrustedSendersBook(false);
+  }, [syncTrustedSenders, trustedSendersLoaded, loadTrustedSendersBook]);
   // Most marketing email is authored against a white background, so dark-mode
   // inversion can wreck logos/banners. With this flag the user opts to render
   // emails on a light surface even while the rest of the app is dark; the
@@ -561,7 +564,7 @@ export default function EmailBodyView({
   const text = picked.text;
   const trusted = isSenderContentTrusted(senderEmail, {
     isLocallyTrusted: isSenderTrusted,
-    syncEnabled: trustedSendersAddressBook,
+    syncEnabled: syncTrustedSenders,
     trustedBookEmails: trustedSenderEmails,
   });
 
@@ -721,12 +724,11 @@ export default function EmailBodyView({
   const onLoadImages = () => setAllowOnce(true);
   const onTrustSender = () => {
     if (senderEmail) {
-      // Keep the local allow-list for instant effect. The server-side "Trusted
-      // Senders" address book (synced across devices) is only written when
-      // the user opted into it - otherwise a book would silently appear in
-      // their contacts (matches the webmail).
+      // Keep the local allow-list for instant effect, and file the sender in
+      // the server-side "Trusted Senders" address book (synced across
+      // devices) unless the user turned that off.
       addTrustedSender(senderEmail);
-      if (trustedSendersAddressBook) {
+      if (syncTrustedSenders) {
         void addToTrustedSendersBook(senderEmail).catch(() => {});
       }
       setAllowOnce(true);

src/components/settings/ContentSendersSettings.tsx

@@ -10,6 +10,7 @@ import { useColors } from '../../theme/colors';
 import { useSettingsStore, type ExternalContentPolicy } from '../../stores/settings-store';
 import { useContactsStore } from '../../stores/contacts-store';
 import { useHasContacts } from '../../lib/capabilities';
+import { isTrustedSendersSyncOn } from '../../lib/trusted-senders';
 import { useLocaleStore } from '../../stores/locale-store';
 
 interface TrustedRow {
@@ -49,9 +50,8 @@ export function ContentSendersSettings() {
 
   useEffect(() => { if (!hydrated) void hydrate(); }, [hydrated, hydrate]);
 
-  // Sync stays off until the user turns it on below (null = never chosen):
-  // opening this pane must not change which senders the viewer trusts.
-  const syncEnabled = !!trustedSendersAddressBook && hasContacts;
+  // On unless the user turned it off below (null = never chosen).
+  const syncEnabled = isTrustedSendersSyncOn(trustedSendersAddressBook, hasContacts);
 
   useEffect(() => {
     if (modalOpen && syncEnabled) void loadTrustedSendersBook();
@@ -179,7 +179,7 @@ export function ContentSendersSettings() {
             description={t('settings.email_behavior.trusted_senders.use_address_book_description', 'Store trusted senders in a dedicated "Trusted Senders" address book so they sync across all your devices')}
           >
             <ToggleSwitch
-              checked={!!trustedSendersAddressBook}
+              checked={syncEnabled}
               onChange={(enabled) => {
                 updateSetting('trustedSendersAddressBook', enabled);
                 if (enabled) void loadTrustedSendersBook();

src/components/settings/UpdatesSettings.tsx

@@ -32,6 +32,7 @@ function installButtonLabel(
 ): string {
   if (!installing) return t('updates.install', 'Install');
   if (progress?.phase === 'installing') return t('updates.installing', 'Installing…');
+  if (progress?.phase === 'verifying') return t('updates.verifying', 'Verifying…');
   if (progress?.progress != null) {
     return t('updates.downloading_pct', 'Downloading {pct}%', { pct: Math.round(progress.progress * 100) });
   }
@@ -213,10 +214,12 @@ export function UpdatesSettings() {
                 style={[
                   styles.progressFill,
                   {
+                    // The download is complete once it is verifying, so the
+                    // bar stays full instead of restarting at 0.
                     width:
-                      installProgress.phase === 'installing'
-                        ? '100%'
-                        : `${Math.round((installProgress.progress ?? 0) * 100)}%`,
+                      installProgress.phase === 'downloading'
+                        ? `${Math.round((installProgress.progress ?? 0) * 100)}%`
+                        : '100%',
                   },
                 ]}
               />
@@ -224,7 +227,9 @@ export function UpdatesSettings() {
             <Text style={styles.progressLabel}>
               {installProgress.phase === 'installing'
                 ? t('updates.opening_installer', 'Opening installer…')
-                : formatProgressLabel(installProgress, t)}
+                : installProgress.phase === 'verifying'
+                  ? t('updates.verifying', 'Verifying…')
+                  : formatProgressLabel(installProgress, t)}
             </Text>
           </View>
         ) : null}

src/lib/__tests__/install-update.test.ts

@@ -0,0 +1,49 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { createHash } from 'node:crypto';
+
+const files = new Map<string, Uint8Array>();
+const digest = vi.fn();
+
+vi.mock('react-native', () => ({ Platform: { OS: 'android' } }));
+vi.mock('expo-file-system', () => ({
+  File: class {
+    constructor(private uri: string) {}
+    async bytes() { return files.get(this.uri) ?? new Uint8Array(); }
+  },
+  Paths: { cache: 'file:///cache' },
+}));
+vi.mock('expo-file-system/legacy', () => ({}));
+vi.mock('expo-intent-launcher', () => ({}));
+vi.mock('expo-crypto', () => ({
+  CryptoDigestAlgorithm: { SHA256: 'SHA-256' },
+  digest: (...args: unknown[]) => digest(...args),
+}));
+
+import { hashFile } from '../install-update';
+
+const sha256Hex = (bytes: Uint8Array) => createHash('sha256').update(bytes).digest('hex');
+
+describe('hashFile', () => {
+  const apk = new TextEncoder().encode('not really an apk');
+
+  beforeEach(() => {
+    files.clear();
+    files.set('file:///cache/app.apk', apk);
+    digest.mockReset();
+  });
+
+  it('hashes the file natively in one call', async () => {
+    digest.mockImplementation(async (_alg: string, data: Uint8Array) => {
+      const out = createHash('sha256').update(data).digest();
+      return out.buffer.slice(out.byteOffset, out.byteOffset + out.byteLength);
+    });
+    expect(await hashFile('file:///cache/app.apk')).toBe(sha256Hex(apk));
+    expect(digest).toHaveBeenCalledTimes(1);
+    expect(digest).toHaveBeenCalledWith('SHA-256', apk);
+  });
+
+  it('falls back to the JS hasher when the native digest fails', async () => {
+    digest.mockRejectedValue(new Error('unavailable'));
+    expect(await hashFile('file:///cache/app.apk')).toBe(sha256Hex(apk));
+  });
+});

src/lib/__tests__/trusted-senders.test.ts

@@ -1,11 +1,26 @@
 import { describe, it, expect } from 'vitest';
-import { isSenderContentTrusted } from '../trusted-senders';
+import { isSenderContentTrusted, isTrustedSendersSyncOn } from '../trusted-senders';
 
 const local = (list: string[]) => (email: string) => list.includes(email.toLowerCase());
 
+describe('isTrustedSendersSyncOn', () => {
+  it('is on unless the user opted out', () => {
+    expect(isTrustedSendersSyncOn(null, true)).toBe(true);
+    expect(isTrustedSendersSyncOn(undefined, true)).toBe(true);
+    expect(isTrustedSendersSyncOn(true, true)).toBe(true);
+    expect(isTrustedSendersSyncOn(false, true)).toBe(false);
+  });
+
+  it('is off on a server without contacts', () => {
+    for (const setting of [null, true, false]) {
+      expect(isTrustedSendersSyncOn(setting, false)).toBe(false);
+    }
+  });
+});
+
 describe('isSenderContentTrusted', () => {
   it('trusts senders on the local allow-list whatever the sync setting', () => {
-    for (const syncEnabled of [null, false, true]) {
+    for (const syncEnabled of [false, true]) {
       expect(isSenderContentTrusted('Alice@Example.com', {
         isLocallyTrusted: local(['alice@example.com']),
         syncEnabled,
@@ -18,8 +33,6 @@ describe('isSenderContentTrusted', () => {
     const opts = { isLocallyTrusted: local([]), trustedBookEmails: ['bob@example.com'] };
     expect(isSenderContentTrusted('Bob@Example.com', { ...opts, syncEnabled: true })).toBe(true);
     expect(isSenderContentTrusted('bob@example.com', { ...opts, syncEnabled: false })).toBe(false);
-    // Never chosen counts as off: the default must not widen trust.
-    expect(isSenderContentTrusted('bob@example.com', { ...opts, syncEnabled: null })).toBe(false);
   });
 
   it('does not trust a sender just because some other list knows them', () => {

src/lib/install-update.ts

@@ -2,20 +2,16 @@ import { Platform } from 'react-native';
 import { File, Paths } from 'expo-file-system';
 import * as FileSystemLegacy from 'expo-file-system/legacy';
 import * as IntentLauncher from 'expo-intent-launcher';
+import * as Crypto from 'expo-crypto';
 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' | 'verifying' | 'installing';
-  /** 0-1 during download; undefined for installing phase */
+  /** 0-1 during download; undefined while verifying and installing */
   progress?: number;
   /** Bytes received during current download */
   bytesWritten?: number;
@@ -31,34 +27,25 @@ export interface InstallParams {
   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;
+function toHex(buffer: ArrayBuffer): string {
+  return Array.from(new Uint8Array(buffer), (b) => b.toString(16).padStart(2, '0')).join('');
 }
 
-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;
+/**
+ * SHA-256 of a downloaded file. The bytes are read and hashed natively:
+ * hashing base64 chunks in JS took longer than the download itself and
+ * looked like a second, slower download. The JS hasher stays as a fallback
+ * for a build without expo-crypto's digest.
+ */
+export async function hashFile(uri: string): Promise<string> {
+  const bytes = await new File(uri).bytes();
+  try {
+    return toHex(await Crypto.digest(Crypto.CryptoDigestAlgorithm.SHA256, bytes));
+  } catch {
+    const hasher = new Sha256();
     hasher.update(bytes);
-    offset += bytes.length;
-    if (totalBytes > 0) {
-      onProgress?.({ phase: 'verifying', progress: offset / totalBytes });
-    }
-    if (bytes.length < length) break;
+    return hasher.digestHex();
   }
-  return hasher.digestHex();
 }
 
 export async function downloadAndInstallApk(
@@ -117,8 +104,8 @@ export async function downloadAndInstallApk(
   // 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);
+    onProgress?.({ phase: 'verifying' });
+    const actual = await hashFile(result.uri);
     if (actual.toLowerCase() !== expectedSha256.toLowerCase()) {
       await tryDelete(result.uri);
       throw new Error(

src/lib/sha256.ts

@@ -1,8 +1,7 @@
-// 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.
+// Minimal SHA-256 implementation. The fallback for verifying APK update
+// downloads when expo-crypto's native digest is unavailable (see
+// `hashFile` in install-update.ts); far too slow to be the main path.
+// Public-domain algorithm (FIPS 180-4).
 
 const K = new Uint32Array([
   0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,

src/lib/trusted-senders.ts

@@ -1,3 +1,13 @@
+/**
+ * Whether "Sync trusted senders to address book" is in effect. Never chosen
+ * (null) counts as on, so trusted senders land in the dedicated "Trusted
+ * Senders" address book out of the box; only the user's opt-out (false), or
+ * a server without contacts, turns it off.
+ */
+export function isTrustedSendersSyncOn(setting: boolean | null | undefined, hasContacts: boolean): boolean {
+  return hasContacts && setting !== false;
+}
+
 /**
  * Whether the viewer may load a sender's remote content (images, tracking
  * pixels) without asking.
@@ -13,8 +23,8 @@ export function isSenderContentTrusted(
   opts: {
     /** The settings store's local allow-list check. */
     isLocallyTrusted: (email: string) => boolean;
-    /** The "Sync trusted senders to address book" setting (null = never chosen, off). */
-    syncEnabled: boolean | null;
+    /** Whether address book sync is in effect (`isTrustedSendersSyncOn`). */
+    syncEnabled: boolean;
     /** Lowercased addresses filed in the "Trusted Senders" book. */
     trustedBookEmails: readonly string[];
   },
@@ -22,5 +32,5 @@ export function isSenderContentTrusted(
   const email = senderEmail?.trim();
   if (!email) return false;
   if (opts.isLocallyTrusted(email)) return true;
-  return !!opts.syncEnabled && opts.trustedBookEmails.includes(email.toLowerCase());
+  return opts.syncEnabled && opts.trustedBookEmails.includes(email.toLowerCase());
 }

src/screens/ComposeScreen.tsx

@@ -33,6 +33,8 @@ import { getEmailInitials } from '../lib/avatar-utils';
 import { useContactsStore, type RecipientSuggestion } from '../stores/contacts-store';
 import { useLocaleStore } from '../stores/locale-store';
 import { useSettingsStore } from '../stores/settings-store';
+import { useHasContacts } from '../lib/capabilities';
+import { isTrustedSendersSyncOn } from '../lib/trusted-senders';
 import { useAccountStore } from '../stores/account-store';
 import { useSendUndoStore } from '../stores/send-undo-store';
 import { toast } from '../stores/toast-store';
@@ -477,6 +479,7 @@ export default function ComposeScreen({ route, navigation }: Props) {
   const subAddressDelimiter = useSettingsStore((s) => s.subAddressDelimiter);
   const preferredIdentityIds = useSettingsStore((s) => s.preferredIdentityIds);
   const trustedSendersAddressBook = useSettingsStore((s) => s.trustedSendersAddressBook);
+  const hasContacts = useHasContacts();
   const updateSetting = useSettingsStore((s) => s.updateSetting);
 
   const quoteLabels = React.useMemo<QuoteHeaderLabels>(() => quoteHeaderLabels(t), [t]);
@@ -2130,7 +2133,7 @@ export default function ComposeScreen({ route, navigation }: Props) {
         const contacts = useContactsStore.getState();
         for (const r of [...outgoing.to, ...(outgoing.cc ?? [])]) {
           settings.addTrustedSender(r.email);
-          if (trustedSendersAddressBook) {
+          if (isTrustedSendersSyncOn(trustedSendersAddressBook, hasContacts)) {
             contacts.addToTrustedSendersBook(r.name ? `${r.name} <${r.email}>` : r.email).catch(() => undefined);
           }
         }

src/stores/settings-store.ts

@@ -127,8 +127,8 @@ interface PersistedSettings {
   // Privacy & content
   externalContentPolicy: ExternalContentPolicy;
   trustedSenders: string[];
-  // null = not decided yet and treated as off; only the user's toggle in
-  // Content & Senders turns it on, false = user opted out.
+  // null = not decided yet and treated as on (isTrustedSendersSyncOn);
+  // false = the user turned it off in Content & Senders.
   trustedSendersAddressBook: boolean | null;
   senderFavicons: boolean;
   hideInlineImageAttachments: boolean;