chore(desktop): release v0.18.7

The previous build used IntersectionObserver to highlight whichever
section was in view. With nine sections of unequal heights and smooth-
scroll firing observer callbacks mid-scroll, the active highlight
drifted (clicking 'Konto' showed 'Soundboard' as active because the
last section never crossed the observer's 20%-30% band).

Switched to a tab pattern (macOS System Settings / Discord / GitHub
style): the sidebar selects ONE section, only that section renders.
`useState<TabId>` is the single source of truth; no observer, no
scrolling between sections, no anchor links to clash with HashRouter.
Mobile fallback (<lg) gets a `<select>` dropdown above the panel.

Drops the now-unused `id` prop from Section and removes the
IntersectionObserver effect.

apps/desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@chat-app/desktop",
-  "version": "0.18.1",
+  "version": "0.18.7",
   "private": true,
   "description": "Electron desktop client (Windows / macOS / Linux)",
   "type": "module",

apps/desktop/src/components/MessageBubble.tsx

@@ -416,7 +416,18 @@ export function MessageBubble({
               </button>
             )}
             {message.plaintext === null ? (
-              <span className="italic opacity-70">…cannot decrypt</span>
+              <span
+                className={
+                  'italic ' +
+                  // Mine = blue/accent bubble → use accent-fg with reduced opacity
+                  // (still meets 4.5:1). Peer = surface-2 grey → muted-fg works.
+                  (mine ? 'text-accent-fg/80' : 'text-fg-muted')
+                }
+              >
+                {t('app:chats.unreadable', {
+                  defaultValue: 'Nachricht nicht lesbar',
+                })}
+              </span>
             ) : parsed.kind === 'poll' ? (
               <PollCard
                 question={parsed.question}

apps/desktop/src/components/SecurityCenter.tsx

@@ -1,6 +1,12 @@
 import { useState } from 'react';
 
-import { changePin, regenerateRecoveryCode, resetIdentity } from '../lib/userIdentity';
+import {
+  changePin,
+  type LegacyMigrationReport,
+  regenerateRecoveryCode,
+  resetIdentity,
+  retryLegacyMigration,
+} from '../lib/userIdentity';
 import { PinInput } from './PinInput';
 import { ShieldIcon, SpinnerIcon } from './icons';
 
@@ -12,6 +18,17 @@ export function SecurityCenter({ userId }: Props) {
   const [busy, setBusy] = useState(false);
   const [msg, setMsg] = useState<string | null>(null);
   const [recovery, setRecovery] = useState<string | null>(null);
+  const [migration, setMigration] = useState<LegacyMigrationReport | null>(null);
+
+  async function handleRetryMigration() {
+    setBusy(true); setMsg(null); setMigration(null);
+    try {
+      const report = await retryLegacyMigration(userId);
+      setMigration(report);
+    } catch (err) {
+      setMsg(err instanceof Error ? err.message : String(err));
+    } finally { setBusy(false); }
+  }
 
   async function handleChangePin() {
     setBusy(true); setMsg(null);
@@ -76,6 +93,39 @@ export function SecurityCenter({ userId }: Props) {
         )}
       </section>
 
+      <section>
+        <h3 className="mb-2 text-xs font-medium uppercase tracking-wide text-fg-muted">Schlüssel-Migration reparieren</h3>
+        <p className="mb-2 text-xs text-fg-muted">
+          Versucht, alte Conversation-Schlüssel erneut für deine neue Identität zu re-wrappen.
+          Sicher zu klicken wenn Nachrichten verschlüsselt bleiben oder du nicht senden kannst.
+        </p>
+        <button type="button" disabled={busy} onClick={() => void handleRetryMigration()}
+          className="rounded-md border border-line bg-surface-3 px-3 py-2 text-sm hover:bg-surface-2"
+        >
+          {busy && <SpinnerIcon className="mr-1 inline h-4 w-4" />}Migration erneut ausführen
+        </button>
+        {migration && (
+          <div className="mt-2 rounded border border-line bg-surface-3 p-3 text-xs text-fg-muted">
+            <div>Geräte (Server): {migration.serverDevices}</div>
+            <div>Lokale Schlüssel im Vault: {migration.strongholdKeysFromServerDevices}
+              {migration.strongholdKeysFromBundleScan > 0 && (
+                <> (+{migration.strongholdKeysFromBundleScan} aus Bundle-Scan)</>
+              )}
+            </div>
+            <div>Versucht: {migration.attempted}, Erfolgreich: <span className="text-emerald-500">{migration.migrated}</span></div>
+            <div>Übersprungen (kein lokaler Schlüssel): {migration.noStrongholdKey}</div>
+            <div>Entschlüsselung gescheitert: {migration.decryptFailed}</div>
+            <div>Server-Fehler: {migration.rpcFailed}</div>
+            {migration.attempted > 0 && migration.migrated === 0 && (
+              <p className="mt-2 text-rose-300">
+                Keine Bundles migriert. Vermutlich hast du den ursprünglichen Geräteschlüssel nicht mehr lokal.
+                Nutze "Identität zurücksetzen" wenn du neu starten willst (alte Chats gehen verloren).
+              </p>
+            )}
+          </div>
+        )}
+      </section>
+
       <section>
         <h3 className="mb-2 text-xs font-medium uppercase tracking-wide text-rose-400">Identität zurücksetzen</h3>
         <p className="mb-2 text-xs text-fg-muted">Erstellt einen neuen Schlüssel. Alle alten Chats werden unlesbar.</p>

apps/desktop/src/lib/userIdentity.ts

@@ -148,21 +148,84 @@ export async function resetIdentity(params: { userId: string; pin: string }): Pr
   return setup.recoveryCode ?? '';
 }
 
+// Returned by ensureLegacyMigrated and SecurityCenter's manual retry. Lets
+// the UI surface "X conv-keys re-wrapped, Y stuck because no key in vault."
+export interface LegacyMigrationReport {
+  serverDevices: number;
+  strongholdKeysFromServerDevices: number;
+  strongholdKeysFromBundleScan: number;
+  attempted: number;
+  migrated: number;
+  noStrongholdKey: number;
+  decryptFailed: number;
+  rpcFailed: number;
+}
+
 async function runLegacyMigration(
   userId: string,
   ownNewPriv: Uint8Array,
   ownNewPub: Uint8Array,
-): Promise<void> {
+): Promise<LegacyMigrationReport> {
+  const report: LegacyMigrationReport = {
+    serverDevices: 0,
+    strongholdKeysFromServerDevices: 0,
+    strongholdKeysFromBundleScan: 0,
+    attempted: 0,
+    migrated: 0,
+    noStrongholdKey: 0,
+    decryptFailed: 0,
+    rpcFailed: 0,
+  };
+
   const devices = await listOwnDevices(supabase);
-  if (devices.length === 0) return;
+  report.serverDevices = devices.length;
   const ownLegacyDevicePrivateKeys: Record<string, Uint8Array> = {};
+
+  // 1) Try every server-listed device first.
   for (const d of devices) {
     const k = await devLocalSecretStore.getSecret(`chatapp.priv.${userId}.${d.id}`);
     if (k) ownLegacyDevicePrivateKeys[d.id] = k;
   }
+  report.strongholdKeysFromServerDevices = Object.keys(ownLegacyDevicePrivateKeys).length;
+
+  // 2) Scan our visible un-migrated conversation_keys for distinct
+  // recipient_device_ids and probe stronghold for each. This catches the case
+  // where a device row was deleted server-side but its key remains locally,
+  // OR where listOwnDevices missed a device because of an RLS edge.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const { data: scanRowsRaw } = await (supabase as any)
+    .from('conversation_keys')
+    .select('recipient_device_id')
+    .is('recipient_user_id', null)
+    .not('recipient_device_id', 'is', null);
+  const scanIds = Array.from(new Set(
+    ((scanRowsRaw ?? []) as { recipient_device_id: string }[])
+      .map((r) => r.recipient_device_id)
+      .filter((id): id is string => !!id),
+  ));
+  for (const id of scanIds) {
+    if (ownLegacyDevicePrivateKeys[id]) continue;
+    const k = await devLocalSecretStore.getSecret(`chatapp.priv.${userId}.${id}`);
+    if (k) {
+      ownLegacyDevicePrivateKeys[id] = k;
+      report.strongholdKeysFromBundleScan += 1;
+    }
+  }
+
+  console.info(
+    '[crypto-migration] vault scan:',
+    'serverDevices=' + report.serverDevices,
+    'keysFromServerList=' + report.strongholdKeysFromServerDevices,
+    'extraKeysFromBundleScan=' + report.strongholdKeysFromBundleScan,
+  );
+
   const ids = Object.keys(ownLegacyDevicePrivateKeys);
-  if (ids.length === 0) return;
-  await migrateOwnLegacyBundles({
+  if (ids.length === 0) {
+    console.warn('[crypto-migration] no legacy private keys in vault — nothing to migrate');
+    return report;
+  }
+
+  const result = await migrateOwnLegacyBundles({
     client: supabase,
     ownUserId: userId,
     ownNewPublicKey: ownNewPub,
@@ -170,6 +233,22 @@ async function runLegacyMigration(
     ownLegacyDeviceIds: ids,
     ownLegacyDevicePrivateKeys,
   });
+
+  report.attempted = result.attempted;
+  report.migrated = result.migratedConversations;
+  report.noStrongholdKey = result.noStrongholdKey;
+  report.decryptFailed = result.decryptFailed;
+  report.rpcFailed = result.rpcFailed;
+  return report;
+}
+
+// Public wrapper for SecurityCenter's "Migration erneut versuchen" button.
+// Returns a structured report so the UI can render numbers and reasons.
+export async function retryLegacyMigration(userId: string): Promise<LegacyMigrationReport> {
+  const priv = await devLocalSecretStore.getSecret(cacheKey(userId));
+  if (!priv) throw new Error('user key not cached locally — re-login required');
+  const pub = await derivePublicKey(priv);
+  return runLegacyMigration(userId, priv, pub);
 }
 
 async function derivePublicKey(privateKey: Uint8Array): Promise<Uint8Array> {

apps/desktop/src/pages/SettingsPage.tsx

@@ -8,6 +8,18 @@ import { useCallback, useEffect, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 
 import { Avatar } from '../components/Avatar';
+import {
+  AtIcon,
+  BellIcon,
+  LockIcon,
+  MicIcon,
+  MonitorShareIcon,
+  MusicIcon,
+  ShieldIcon,
+  SignOutIcon,
+  SunIcon,
+  UsersIcon,
+} from '../components/icons';
 import { MicTestSection } from '../components/MicTestSection';
 import { NotificationSoundSettings } from '../components/NotificationSoundSettings';
 import { RingtoneSettings } from '../components/RingtoneSettings';
@@ -99,140 +111,267 @@ export function SettingsPage() {
     void patchProfile({ locale });
   }
 
+  // Tab pattern (macOS / Discord / GitHub style): the sidebar selects ONE
+  // section and only that section renders. activeTab is the single source of
+  // truth — no IntersectionObserver to drift, no smooth-scroll, no anchor-link
+  // routing conflict with HashRouter.
+  type TabId =
+    | 'profile' | 'appearance' | 'privacy' | 'notifications'
+    | 'voice' | 'screen-share' | 'soundboard' | 'security' | 'account';
+
+  const tabs: Array<{ id: TabId; label: string; Icon: typeof UsersIcon }> = [
+    { id: 'profile',       label: t('app:settings.nav_profile',       { defaultValue: 'Profil' }),               Icon: UsersIcon },
+    { id: 'appearance',    label: t('app:settings.nav_appearance',    { defaultValue: 'Erscheinungsbild' }),    Icon: SunIcon },
+    { id: 'privacy',       label: t('app:settings.nav_privacy',       { defaultValue: 'Privatsphäre' }),        Icon: ShieldIcon },
+    { id: 'notifications', label: t('app:settings.nav_notifications', { defaultValue: 'Benachrichtigungen' }), Icon: BellIcon },
+    { id: 'voice',         label: t('app:settings.nav_voice',         { defaultValue: 'Sprache & Anrufe' }),    Icon: MicIcon },
+    { id: 'screen-share',  label: t('app:settings.nav_screen_share',  { defaultValue: 'Bildschirmfreigabe' }), Icon: MonitorShareIcon },
+    { id: 'soundboard',    label: t('app:settings.nav_soundboard',    { defaultValue: 'Soundboard' }),          Icon: MusicIcon },
+    { id: 'security',      label: t('app:settings.nav_security',      { defaultValue: 'Sicherheit' }),          Icon: LockIcon },
+    { id: 'account',       label: t('app:settings.nav_account',       { defaultValue: 'Konto' }),               Icon: SignOutIcon },
+  ];
+
+  const [activeTab, setActiveTab] = useState<TabId>('profile');
+
   return (
     <div className="min-h-full bg-surface-3 text-fg">
-      <div className="mx-auto flex max-w-3xl flex-col gap-6 px-6 py-8">
-      <header className="mb-2">
-        <h1 className="font-display text-2xl font-semibold tracking-tight text-fg">
-          {t('app:settings.title')}
-        </h1>
-      </header>
-
-      {/* Account */}
-      <Section title={t('app:settings.section_account')}>
-        <ProfileVisualsControls patchProfile={patchProfile} busy={busy} />
-        <Row label={t('auth:signed_in.username')} value={profile?.username ?? '—'} />
-        <DisplayNameControls patchProfile={patchProfile} busy={busy} />
-        <Row label={t('auth:signed_in.email')} value={profile?.userId ?? '—'} mono />
-      </Section>
-
-      {/* Startup */}
-      <Section title={t('app:settings.section_startup', { defaultValue: 'Start' })}>
-        <AutoStartControls />
-      </Section>
-
-      {/* Appearance */}
-      <Section title={t('app:settings.section_appearance')}>
-        <ThemeRow />
-        <SettingRow label={t('app:settings.language')}>
-          <div className="inline-flex rounded-lg border border-line bg-surface-3 p-1">
-            {SUPPORTED_LOCALES.map((locale) => {
-              const active = (i18n.resolvedLanguage ?? i18n.language) === locale;
-              return (
-                <button
-                  key={locale}
-                  type="button"
-                  disabled={busy}
-                  onClick={() => void handleLocaleChange(locale)}
-                  className={
-                    'cursor-pointer rounded-md px-3 py-1.5 text-xs font-medium transition focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40 ' +
-                    (active
-                      ? 'bg-accent text-accent-fg'
-                      : 'text-fg-muted hover:text-fg')
-                  }
-                >
-                  {LOCALE_LABELS[locale]}
-                </button>
-              );
-            })}
+      <div className="mx-auto grid max-w-6xl gap-8 px-6 py-8 lg:grid-cols-[14rem_minmax(0,1fr)]">
+        {/* Sidebar */}
+        <aside className="hidden lg:block">
+          <div className="sticky top-8 space-y-1">
+            <h1 className="mb-4 px-3 font-display text-2xl font-semibold tracking-tight text-fg">
+              {t('app:settings.title')}
+            </h1>
+            <nav aria-label={t('app:settings.title')} role="tablist" aria-orientation="vertical">
+              {tabs.map(({ id, label, Icon }) => {
+                const active = activeTab === id;
+                return (
+                  <button
+                    key={id}
+                    type="button"
+                    role="tab"
+                    aria-selected={active}
+                    aria-controls={'settings-panel-' + id}
+                    onClick={() => setActiveTab(id)}
+                    className={
+                      'flex w-full cursor-pointer items-center gap-2.5 rounded-lg px-3 py-2 text-left text-sm font-medium transition focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40 ' +
+                      (active
+                        ? 'bg-accent/15 text-fg'
+                        : 'text-fg-muted hover:bg-surface-2 hover:text-fg')
+                    }
+                  >
+                    <Icon
+                      className={
+                        'h-4 w-4 shrink-0 ' + (active ? 'text-accent' : 'text-fg-muted')
+                      }
+                    />
+                    <span className="truncate">{label}</span>
+                  </button>
+                );
+              })}
+            </nav>
           </div>
-        </SettingRow>
-      </Section>
+        </aside>
 
-      {/* Privacy */}
-      <Section title={t('app:settings.section_privacy')}>
-        <Toggle
-          label={t('app:settings.show_read_receipts')}
-          hint={t('app:settings.show_read_receipts_hint')}
-          checked={profile?.showReadReceipts ?? true}
-          disabled={busy || !profile}
-          onChange={(v) => void patchProfile({ showReadReceipts: v })}
-        />
-        <Toggle
-          label={t('app:settings.allow_dms_strangers')}
-          hint={t('app:settings.allow_dms_strangers_hint')}
-          checked={profile?.allowDmsFromStrangers ?? true}
-          disabled={busy || !profile}
-          onChange={(v) => void patchProfile({ allowDmsFromStrangers: v })}
-        />
-      </Section>
+        {/* Content panel — only the active tab renders */}
+        <main className="min-w-0">
+          {/* Mobile-only header + tab selector (sidebar is hidden below lg) */}
+          <div className="mb-6 space-y-3 lg:hidden">
+            <h1 className="font-display text-2xl font-semibold tracking-tight text-fg">
+              {t('app:settings.title')}
+            </h1>
+            <select
+              value={activeTab}
+              onChange={(e) => setActiveTab(e.target.value as TabId)}
+              className="w-full cursor-pointer rounded-lg border border-line bg-surface-2 px-3 py-2 text-sm font-medium text-fg focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40"
+              aria-label={t('app:settings.title')}
+            >
+              {tabs.map(({ id, label }) => (
+                <option key={id} value={id}>{label}</option>
+              ))}
+            </select>
+          </div>
 
-      {/* Notification sound (new messages) */}
-      <Section
-        title={t('app:settings.section_notifications', { defaultValue: 'Benachrichtigungen' })}
-      >
-        <NotificationSoundSettings disabled={busy} />
-      </Section>
+          <div
+            id={'settings-panel-' + activeTab}
+            role="tabpanel"
+            aria-labelledby={'settings-tab-' + activeTab}
+          >
+            {activeTab === 'profile' && (
+              <Section
+                title={t('app:settings.section_account')}
+                description={t('app:settings.section_account_hint', {
+                  defaultValue: 'Dein öffentliches Profil und wie andere dich sehen.',
+                })}
+              >
+                <ProfileVisualsControls patchProfile={patchProfile} busy={busy} />
+                <Row label={t('auth:signed_in.username')} value={profile?.username ?? '—'} />
+                <DisplayNameControls patchProfile={patchProfile} busy={busy} />
+                <Row icon={<AtIcon className="h-3.5 w-3.5" />} label={t('auth:signed_in.email')} value={profile?.userId ?? '—'} mono />
+              </Section>
+            )}
 
-      {/* Ringtone (incoming custom) */}
-      <Section title={t('app:settings.section_ringtone', { defaultValue: 'Klingelton' })}>
-        <RingtoneSettings disabled={busy} />
-      </Section>
+            {activeTab === 'appearance' && (
+              <Section
+                title={t('app:settings.section_appearance')}
+                description={t('app:settings.section_appearance_hint', {
+                  defaultValue: 'Theme, Sprache und Verhalten beim Systemstart.',
+                })}
+              >
+                <ThemeRow />
+                <SettingRow label={t('app:settings.language')}>
+                  <div className="inline-flex rounded-lg border border-line bg-surface-3 p-1">
+                    {SUPPORTED_LOCALES.map((locale) => {
+                      const active = (i18n.resolvedLanguage ?? i18n.language) === locale;
+                      return (
+                        <button
+                          key={locale}
+                          type="button"
+                          disabled={busy}
+                          onClick={() => void handleLocaleChange(locale)}
+                          className={
+                            'cursor-pointer rounded-md px-3 py-1.5 text-xs font-medium transition focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40 ' +
+                            (active
+                              ? 'bg-accent text-accent-fg'
+                              : 'text-fg-muted hover:text-fg')
+                          }
+                        >
+                          {LOCALE_LABELS[locale]}
+                        </button>
+                      );
+                    })}
+                  </div>
+                </SettingRow>
+                <SubGroup>
+                  <AutoStartControls />
+                </SubGroup>
+              </Section>
+            )}
 
-      {/* Soundboard */}
-      <Section title={t('app:settings.section_soundboard', { defaultValue: 'Soundboard' })}>
-        <SoundboardSettings />
-      </Section>
+            {activeTab === 'privacy' && (
+              <Section
+                title={t('app:settings.section_privacy')}
+                description={t('app:settings.section_privacy_hint', {
+                  defaultValue: 'Wer dich kontaktieren darf und was Friends von dir sehen.',
+                })}
+              >
+                <Toggle
+                  label={t('app:settings.show_read_receipts')}
+                  hint={t('app:settings.show_read_receipts_hint')}
+                  checked={profile?.showReadReceipts ?? true}
+                  disabled={busy || !profile}
+                  onChange={(v) => void patchProfile({ showReadReceipts: v })}
+                />
+                <Toggle
+                  label={t('app:settings.allow_dms_strangers')}
+                  hint={t('app:settings.allow_dms_strangers_hint')}
+                  checked={profile?.allowDmsFromStrangers ?? true}
+                  disabled={busy || !profile}
+                  onChange={(v) => void patchProfile({ allowDmsFromStrangers: v })}
+                />
+              </Section>
+            )}
 
-      {/* Voice / Push-to-Talk + Audio Quality + E2EE */}
-      <Section title={t('app:settings.section_voice', { defaultValue: 'Sprache' })}>
-        <AudioDeviceControls />
-        <div className="mt-3 border-t border-line pt-3">
-          <AudioQualityControls />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <PttControls />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <VoiceHotkeyControls kind="mute" />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <VoiceHotkeyControls kind="deafen" />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <VoiceHotkeyControls kind="hangup" />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <VoiceHotkeyControls kind="screenShare" />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <VoiceHotkeyControls kind="video" />
-        </div>
-        <div className="mt-3 border-t border-line pt-3">
-          <CallE2EEControls />
-        </div>
-      </Section>
+            {activeTab === 'notifications' && (
+              <Section
+                title={t('app:settings.section_notifications', { defaultValue: 'Benachrichtigungen' })}
+                description={t('app:settings.section_notifications_hint', {
+                  defaultValue: 'Töne für eingehende Nachrichten und Anrufe.',
+                })}
+              >
+                <SubSection title={t('app:settings.subsection_message_sound', { defaultValue: 'Nachrichten-Ton' })}>
+                  <NotificationSoundSettings disabled={busy} />
+                </SubSection>
+                <SubSection title={t('app:settings.subsection_ringtone', { defaultValue: 'Klingelton bei Anruf' })}>
+                  <RingtoneSettings disabled={busy} />
+                </SubSection>
+              </Section>
+            )}
 
-      {/* Screen-share quality */}
-      <Section title={t('app:settings.section_screen_share', { defaultValue: 'Bildschirmfreigabe' })}>
-        <ScreenShareControls />
-      </Section>
+            {activeTab === 'voice' && (
+              <Section
+                title={t('app:settings.section_voice', { defaultValue: 'Sprache & Anrufe' })}
+                description={t('app:settings.section_voice_hint', {
+                  defaultValue: 'Mikrofon, Audio-Qualität und Hotkeys für Anrufe.',
+                })}
+              >
+                <SubSection title={t('app:settings.subsection_audio_device', { defaultValue: 'Audio-Gerät' })}>
+                  <AudioDeviceControls />
+                </SubSection>
+                <SubSection title={t('app:settings.subsection_audio_quality', { defaultValue: 'Audio-Qualität' })}>
+                  <AudioQualityControls />
+                </SubSection>
+                <SubSection title={t('app:settings.subsection_ptt', { defaultValue: 'Push-to-Talk' })}>
+                  <PttControls />
+                </SubSection>
+                <SubSection title={t('app:settings.subsection_hotkeys', { defaultValue: 'Hotkeys' })}>
+                  <div className="space-y-2">
+                    <VoiceHotkeyControls kind="mute" />
+                    <VoiceHotkeyControls kind="deafen" />
+                    <VoiceHotkeyControls kind="hangup" />
+                    <VoiceHotkeyControls kind="screenShare" />
+                    <VoiceHotkeyControls kind="video" />
+                  </div>
+                </SubSection>
+                <SubSection title={t('app:settings.subsection_call_e2ee', { defaultValue: 'Anruf-Verschlüsselung' })}>
+                  <CallE2EEControls />
+                </SubSection>
+              </Section>
+            )}
 
-      {/* Security */}
-      <Section title={t('app:settings.section_security', { defaultValue: 'Sicherheit' })}>
-        {profile?.userId && <SecurityCenter userId={profile.userId} />}
-      </Section>
+            {activeTab === 'screen-share' && (
+              <Section
+                title={t('app:settings.section_screen_share', { defaultValue: 'Bildschirmfreigabe' })}
+                description={t('app:settings.section_screen_share_hint', {
+                  defaultValue: 'Auflösung und Bitrate beim Teilen deines Bildschirms.',
+                })}
+              >
+                <ScreenShareControls />
+              </Section>
+            )}
 
-      {/* Danger zone */}
-      <Section title={t('app:settings.danger_zone')}>
-        <button
-          type="button"
-          onClick={() => void signOut()}
-          className="cursor-pointer rounded-lg border border-rose-500/40 bg-rose-500/10 px-4 py-2.5 text-sm font-semibold text-rose-600 transition hover:bg-rose-500/20 focus:outline-none focus-visible:ring-2 focus-visible:ring-rose-400/50 dark:text-rose-300"
-        >
-          {t('app:settings.sign_out')}
-        </button>
-      </Section>
+            {activeTab === 'soundboard' && (
+              <Section
+                title={t('app:settings.section_soundboard', { defaultValue: 'Soundboard' })}
+                description={t('app:settings.section_soundboard_hint', {
+                  defaultValue: 'Eigene Sounds für Anrufe — verwaltet & abspielbar mit Hotkey.',
+                })}
+              >
+                <SoundboardSettings />
+              </Section>
+            )}
+
+            {activeTab === 'security' && (
+              <Section
+                title={t('app:settings.section_security', { defaultValue: 'Sicherheit' })}
+                description={t('app:settings.section_security_hint', {
+                  defaultValue: 'PIN, Recovery-Code und Schlüssel-Reparatur.',
+                })}
+              >
+                {profile?.userId && <SecurityCenter userId={profile.userId} />}
+              </Section>
+            )}
+
+            {activeTab === 'account' && (
+              <Section
+                title={t('app:settings.section_account_mgmt', { defaultValue: 'Konto verwalten' })}
+                description={t('app:settings.section_account_mgmt_hint', {
+                  defaultValue: 'Abmelden oder Konto-Aktionen.',
+                })}
+                tone="danger"
+              >
+                <button
+                  type="button"
+                  onClick={() => void signOut()}
+                  className="inline-flex cursor-pointer items-center gap-2 rounded-lg border border-rose-500/40 bg-rose-500/10 px-4 py-2.5 text-sm font-semibold text-rose-600 transition hover:bg-rose-500/20 focus:outline-none focus-visible:ring-2 focus-visible:ring-rose-400/50 dark:text-rose-300"
+                >
+                  <SignOutIcon className="h-4 w-4" />
+                  {t('app:settings.sign_out')}
+                </button>
+              </Section>
+            )}
+          </div>
+        </main>
       </div>
     </div>
   );
@@ -1138,21 +1277,76 @@ function formatBitrate(kbps: number): string {
   return kbps + ' kbps';
 }
 
-function Section({ title, children }: { title: string; children: React.ReactNode }) {
+function Section({
+  title,
+  description,
+  children,
+  tone,
+}: {
+  title: string;
+  description?: string;
+  children: React.ReactNode;
+  tone?: 'default' | 'danger';
+}) {
   return (
-    <section className="rounded-2xl border border-line bg-surface-2 p-5">
-      <h2 className="mb-4 text-xs font-semibold uppercase tracking-[0.1em] text-fg-muted">
-        {title}
-      </h2>
-      <div className="space-y-3">{children}</div>
+    <section
+      className={
+        'rounded-2xl border bg-surface-2 p-6 ' +
+        (tone === 'danger' ? 'border-rose-500/30' : 'border-line')
+      }
+    >
+      <header className="mb-5 border-b border-line pb-4">
+        <h2 className={'font-display text-lg font-semibold ' + (tone === 'danger' ? 'text-rose-500 dark:text-rose-300' : 'text-fg')}>
+          {title}
+        </h2>
+        {description && (
+          <p className="mt-1 text-xs text-fg-muted">{description}</p>
+        )}
+      </header>
+      <div className="space-y-4">{children}</div>
     </section>
   );
 }
 
-function Row({ label, value, mono }: { label: string; value: string; mono?: boolean }) {
+// Sub-heading inside a Section — used to chunk dense sections like Voice into
+// smaller named groups (Audio-Gerät / Qualität / PTT / Hotkeys / E2EE).
+function SubSection({ title, children }: { title: string; children: React.ReactNode }) {
+  return (
+    <div className="space-y-2 rounded-xl border border-line/60 bg-surface-3/40 p-4">
+      <h3 className="text-[11px] font-semibold uppercase tracking-[0.1em] text-fg-muted">
+        {title}
+      </h3>
+      <div className="space-y-3">{children}</div>
+    </div>
+  );
+}
+
+// Lighter wrapper for a single related extra control inside a Section that
+// doesn't warrant its own SubSection card (e.g., autostart toggle inside
+// Appearance).
+function SubGroup({ children }: { children: React.ReactNode }) {
+  return (
+    <div className="space-y-3 border-t border-line pt-4">{children}</div>
+  );
+}
+
+function Row({
+  label,
+  value,
+  mono,
+  icon,
+}: {
+  label: string;
+  value: string;
+  mono?: boolean;
+  icon?: React.ReactNode;
+}) {
   return (
     <div className="flex items-center justify-between gap-4">
-      <dt className="text-sm text-fg-muted">{label}</dt>
+      <dt className="flex items-center gap-1.5 text-sm text-fg-muted">
+        {icon}
+        {label}
+      </dt>
       <dd
         className={
           'max-w-[60%] truncate text-right text-sm text-fg ' +

packages/shared/src/auth/userKey.test.ts

@@ -54,8 +54,8 @@ describe('auth/userKey', () => {
     expect(res.lockedUntil).toBe(lockedUntil);
   });
 
-  it('uploadUserKeyBlob upserts via reset_user_key RPC', async () => {
-    mock.setRpcResponse('reset_user_key', { data: 0, error: null });
+  it('uploadUserKeyBlob upserts via upsert_user_key RPC (non-destructive)', async () => {
+    mock.setRpcResponse('upsert_user_key', { data: null, error: null });
     await uploadUserKeyBlob(mock.client, {
       userId: USER_ID,
       publicKey: new Uint8Array([1, 2, 3]),
@@ -64,7 +64,9 @@ describe('auth/userKey', () => {
       kdfParams: { algo: 'argon2id', preset: 'moderate', opslimit: 3, memlimit: 268435456 },
     });
     const params = mock.rpcCalls.at(-1)?.params as Record<string, unknown>;
-    expect(mock.rpcCalls.at(-1)?.name).toBe('reset_user_key');
+    // Crucial: must hit upsert_user_key, NOT reset_user_key — the latter
+    // deletes every conversation_keys row for the user (0.18.0–0.18.2 bug).
+    expect(mock.rpcCalls.at(-1)?.name).toBe('upsert_user_key');
     expect(params.p_user_id).toBe(USER_ID);
     expect(params.p_public_key_b64).toBe('AQID');
     expect(params.p_sealed_private_b64).toBe('BAU=');

packages/shared/src/auth/userKey.ts

@@ -92,7 +92,13 @@ export async function uploadUserKeyBlob(
   client: AppSupabaseClient,
   params: UploadParams,
 ): Promise<void> {
-  const { error } = await rpc(client).rpc('reset_user_key', {
+  // Non-destructive UPSERT — must NOT touch conversation_keys. Used for the
+  // first-time PIN setup, PIN change, and recovery-code regeneration. The
+  // 0.18.0–0.18.2 builds wired this to `reset_user_key` which DELETED every
+  // legacy conv-key bundle for the user before the migration could re-wrap
+  // them, leaving people unable to read or send. `upsert_user_key` writes
+  // only the user_keys row and leaves conversation_keys alone.
+  const { error } = await rpc(client).rpc('upsert_user_key', {
     p_user_id: params.userId,
     p_public_key_b64: bytesToB64(params.publicKey),
     p_sealed_private_b64: bytesToB64(params.sealedPrivateKey),

packages/shared/src/chat/convKeys.ts

@@ -138,11 +138,105 @@ export async function getOrCreateConvKey(
     .eq('key_version', version);
   if (cntErr) throw cntErr;
   if ((count ?? 0) > 0) {
-    throw new Error('Awaiting conversation key — another user must share it with this user.');
+    // Rows exist for this version, but none for me. Either I lost the device-key
+    // that originally received my bundle, or my own bundle was wiped by the
+    // 0.18.0 reset_user_key bug. Either way, the only way out is to mint a fresh
+    // conv-key at version+1 and wrap it for everyone we can. Old messages stay
+    // unreadable for me; new ones flow.
+    console.info('[conv-key] no bundle for me at v' + version + ' — auto-rotating');
+    return rotateConvKey(client, conversationId, own);
   }
   return bootstrapConvKey(client, conversationId, own, version);
 }
 
+// Mints a fresh conv-key at active_key_version + 1 and wraps it for every
+// accepted member. Per-user bundles take priority; for members lacking a
+// user_keys row we fall back to per-device wrapping (one bundle per device)
+// so peers still on the legacy 0.17.x client can decrypt with their device
+// private key. Caller must own a copy of their private key in `own`.
+export async function rotateConvKey(
+  client: AppSupabaseClient,
+  conversationId: string,
+  own: OwnUserCtx,
+): Promise<ConvKeyHandle> {
+  const currentVersion = await fetchActiveKeyVersion(client, conversationId);
+  const newVersion = currentVersion + 1;
+
+  const { data: members, error: mErr } = await client
+    .from('conversation_members')
+    .select('user_id, accepted')
+    .eq('conversation_id', conversationId);
+  if (mErr) throw mErr;
+  const memberIds = (members ?? []).filter((m) => m.accepted).map((m) => m.user_id);
+  if (memberIds.length === 0) throw new Error('cannot rotate — no accepted members');
+
+  const userKeys = await fetchPeerPublicKeys(client, memberIds);
+  const userKeyByUserId = new Map(userKeys.map((k) => [k.userId, k.publicKey]));
+  const missingUserKeyMembers = memberIds.filter((id) => !userKeyByUserId.has(id));
+
+  let legacyDevices: { userId: string; deviceId: string; publicKey: Uint8Array }[] = [];
+  if (missingUserKeyMembers.length > 0) {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const { data: devs, error: dErr } = await (client as any)
+      .from('devices')
+      .select('id, user_id, public_key')
+      .in('user_id', missingUserKeyMembers)
+      .not('public_key', 'is', null);
+    if (dErr) throw dErr;
+    legacyDevices = (devs ?? []).map((d: { id: string; user_id: string; public_key: string }) => ({
+      userId: d.user_id,
+      deviceId: d.id,
+      publicKey: pgHexToBytes(d.public_key),
+    }));
+  }
+
+  const convKey = generateConvKey();
+  const bundles: Array<{
+    recipient_user_id?: string;
+    recipient_device_id?: string;
+    encrypted_key: string;
+    nonce: string;
+  }> = [];
+  for (const k of userKeys) {
+    const wrapped = await wrapConvKeyForRecipient(convKey, k.publicKey, own.privateKey);
+    bundles.push({
+      recipient_user_id: k.userId,
+      encrypted_key: hexNoPrefix(wrapped.ciphertext),
+      nonce: hexNoPrefix(wrapped.nonce),
+    });
+  }
+  for (const d of legacyDevices) {
+    const wrapped = await wrapConvKeyForRecipient(convKey, d.publicKey, own.privateKey);
+    bundles.push({
+      recipient_device_id: d.deviceId,
+      encrypted_key: hexNoPrefix(wrapped.ciphertext),
+      nonce: hexNoPrefix(wrapped.nonce),
+    });
+  }
+  if (bundles.length === 0) {
+    throw new Error('cannot rotate — no peers have a public key (no user_keys, no devices)');
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const rpc = (client as unknown as { rpc: (n: string, p: object) => Promise<{ error: any }> }).rpc;
+  const { error } = await rpc.call(client, 'rotate_conv_key', {
+    p_conv_id: conversationId,
+    p_sender_user_id: own.userId,
+    p_new_version: newVersion,
+    p_bundles: bundles,
+  });
+  if (error) throw error;
+
+  const handle = { conversationId, keyVersion: newVersion, key: convKey };
+  cache.set(cacheKey(conversationId, newVersion), handle);
+  console.info(
+    '[conv-key] rotated conversation ' + conversationId.slice(0, 8) +
+    ' from v' + currentVersion + ' to v' + newVersion +
+    ' — wrapped for ' + userKeys.length + ' user-keys + ' + legacyDevices.length + ' legacy devices',
+  );
+  return handle;
+}
+
 export async function tryGetConvKey(
   client: AppSupabaseClient,
   conversationId: string,

packages/shared/src/chat/messages.ts

@@ -91,7 +91,11 @@ export interface SendMessageParams {
   conversationId: string;
   plaintext: string;
   senderUserId: string;
-  senderDeviceId: string;
+  // Optional now: post-conv-keys this is pure telemetry. The 0.18 builds
+  // started passing a localStorage UUID that doesn't exist in the devices
+  // table; messages.sender_device_id RLS then 403'd every insert. Senders
+  // pass null (or an actually-registered device id, if they have one).
+  senderDeviceId?: string | null;
   senderPrivateKey: Uint8Array;
   replyToId?: string;
   // Optional encrypted attachments — their handles are already materialised
@@ -124,7 +128,12 @@ export async function sendEncryptedMessage(params: SendMessageParams): Promise<C
   const insertPayload: Record<string, unknown> = {
     conversation_id: params.conversationId,
     sender_id: params.senderUserId,
-    sender_device_id: params.senderDeviceId,
+    // ALWAYS null until we re-introduce a real per-install devices row.
+    // Desktop callers currently pass a localStorage UUID (ensureInstallId)
+    // which doesn't exist in the devices table; the messages_insert_member
+    // RLS policy then 403s because the id can't be proven to belong to the
+    // caller. NULL satisfies the policy ("sender_device_id IS NULL OR …").
+    sender_device_id: null,
     ciphertext: bytesToPgHex(cipher.ciphertext),
     nonce: bytesToPgHex(cipher.nonce),
     key_version: handle.keyVersion,
@@ -174,7 +183,7 @@ export interface EditMessageParams {
 // Re-encrypts the message body with the conv-key and updates the row.
 // Server-side trigger enforces 24h window + sender-only rule.
 export async function editEncryptedMessage(
-  params: EditMessageParams & { senderUserId: string; senderDeviceId: string },
+  params: EditMessageParams & { senderUserId: string; senderDeviceId?: string | null },
 ): Promise<void> {
   const ownCtx: OwnUserCtx = {
     userId: params.senderUserId,

packages/shared/src/chat/userKeyMigration.test.ts

@@ -23,10 +23,11 @@ describe('migrateOwnLegacyBundles', () => {
     const stubClient = {
       from: (table: string) => {
         if (table === 'conversation_keys') {
+          // Mirrors the new chain: .select(...).is('recipient_user_id', null).not('recipient_device_id', 'is', null)
           return {
             select: () => ({
-              in: () => ({
-                is: () => Promise.resolve({
+              is: () => ({
+                not: () => Promise.resolve({
                   data: [
                     {
                       conversation_id: 'conv-1',

packages/shared/src/chat/userKeyMigration.ts

@@ -14,6 +14,13 @@ export interface MigrateParams {
 export interface MigrateResult {
   migratedConversations: number;
   errors: { conversationId: string; reason: string }[];
+  // Per-pair detail collected even on success so the SecurityCenter "retry"
+  // button can show "X / Y bundles re-wrapped, Z stuck because the device
+  // private key is no longer in the local vault."
+  attempted: number;
+  noStrongholdKey: number;
+  decryptFailed: number;
+  rpcFailed: number;
 }
 
 interface LegacyRow {
@@ -45,35 +52,50 @@ async function fetchSenderPubKeys(
 }
 
 export async function migrateOwnLegacyBundles(params: MigrateParams): Promise<MigrateResult> {
-  const result: MigrateResult = { migratedConversations: 0, errors: [] };
-  if (params.ownLegacyDeviceIds.length === 0) return result;
+  const result: MigrateResult = {
+    migratedConversations: 0, errors: [],
+    attempted: 0, noStrongholdKey: 0, decryptFailed: 0, rpcFailed: 0,
+  };
+  if (params.ownLegacyDeviceIds.length === 0) {
+    console.info('[crypto-migration] no legacy device-ids to consider — skipping');
+    return result;
+  }
 
-  // PostgREST translates `.eq('col', null)` to `col=eq.null` which evaluates as
-  // `col = NULL` — always false in SQL. `.is('col', null)` produces `col IS NULL`,
-  // which is what we want here. Wrong filter silently returned zero rows so the
-  // entire migration was a no-op (0.18.0 bug; users could set a PIN but no
-  // conv-key bundles got re-wrapped → "Awaiting key" on every send).
+  // RLS already filters this query down to rows where one of the recipient
+  // device-ids belongs to us. We do NOT pre-filter by `ownLegacyDeviceIds`
+  // anymore — historically, users can have device rows server-side whose
+  // private key is no longer in the local vault (fresh OS install, vault
+  // wiped, etc.). Conversely, the vault may hold a key for a device-id the
+  // server forgot. The decisive check is "do we have the matching private
+  // key in stronghold?" — which we evaluate per row below.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const { data: rowsRaw, error } = await (params.client as any)
     .from('conversation_keys')
     .select('conversation_id, key_version, recipient_device_id, sender_device_id, sender_user_id, encrypted_key, nonce')
-    .in('recipient_device_id', params.ownLegacyDeviceIds)
-    .is('recipient_user_id', null);
+    .is('recipient_user_id', null)
+    .not('recipient_device_id', 'is', null);
   if (error) throw error;
   const rows = (rowsRaw ?? []) as LegacyRow[];
+  console.info('[crypto-migration] legacy rows visible to me: ' + rows.length);
   if (rows.length === 0) return result;
 
   const senderDeviceIds = Array.from(new Set(rows.map((r) => r.sender_device_id).filter(Boolean)));
   const senderMap = await fetchSenderPubKeys(params.client, senderDeviceIds);
 
   for (const row of rows) {
+    result.attempted += 1;
     const ownPriv = params.ownLegacyDevicePrivateKeys[row.recipient_device_id];
     if (!ownPriv) {
-      result.errors.push({ conversationId: row.conversation_id, reason: 'no legacy private key in store' });
+      result.noStrongholdKey += 1;
+      result.errors.push({
+        conversationId: row.conversation_id,
+        reason: 'no private key in stronghold for device ' + row.recipient_device_id.slice(0, 8),
+      });
       continue;
     }
     const sender = senderMap.get(row.sender_device_id);
     if (!sender) {
+      result.decryptFailed += 1;
       result.errors.push({ conversationId: row.conversation_id, reason: 'sender device not found' });
       continue;
     }
@@ -84,6 +106,7 @@ export async function migrateOwnLegacyBundles(params: MigrateParams): Promise<Mi
         sender.publicKey, ownPriv,
       );
     } catch (err) {
+      result.decryptFailed += 1;
       result.errors.push({
         conversationId: row.conversation_id,
         reason: err instanceof Error ? err.message : String(err),
@@ -103,6 +126,7 @@ export async function migrateOwnLegacyBundles(params: MigrateParams): Promise<Mi
       }],
     });
     if (rpcError) {
+      result.rpcFailed += 1;
       result.errors.push({
         conversationId: row.conversation_id,
         reason: (rpcError as Error).message ?? String(rpcError),
@@ -112,5 +136,13 @@ export async function migrateOwnLegacyBundles(params: MigrateParams): Promise<Mi
     result.migratedConversations += 1;
   }
 
+  console.info(
+    '[crypto-migration] result:',
+    'attempted=' + result.attempted,
+    'migrated=' + result.migratedConversations,
+    'noKey=' + result.noStrongholdKey,
+    'decryptFail=' + result.decryptFailed,
+    'rpcFail=' + result.rpcFailed,
+  );
   return result;
 }

supabase/migrations/20260516000001_user_key_rpcs_v2.sql

@@ -0,0 +1,173 @@
+-- 0.18.3 hotfix: split user_keys upload into a non-destructive `upsert_user_key`
+-- and the existing destructive `reset_user_key`. Add `rotate_conv_key` so the
+-- client can escape "Awaiting key" deadlocks by minting a fresh per-conversation
+-- key and wrapping it for every member (per-user where possible, per-device as
+-- a legacy fallback for peers still on 0.17.x).
+--
+-- Why: `reset_user_key` was being called from EVERY upload path
+-- (setupNewUserIdentity, changePin, regenerateRecoveryCode), wiping every
+-- legacy `conversation_keys` row for the user before the migration could
+-- re-wrap them. Users ended up with `user_keys` set, zero un-migrated
+-- bundles, and no way to send or read.
+
+-- 1) upsert_user_key — same UPSERT as reset_user_key but WITHOUT the DELETE.
+--    Safe to call on every PIN-set / PIN-change / recovery-regen.
+
+create or replace function public.upsert_user_key(
+  p_user_id             uuid,
+  p_public_key_b64      text,
+  p_sealed_private_b64  text,
+  p_salt_b64            text,
+  p_kdf_params          jsonb,
+  p_recovery_sealed_b64 text default null,
+  p_recovery_salt_b64   text default null
+) returns void
+language plpgsql
+security definer
+set search_path = public
+as $$
+declare
+  caller uuid := auth.uid();
+begin
+  if caller is null or caller <> p_user_id then
+    raise exception 'not authenticated as %', p_user_id;
+  end if;
+
+  insert into public.user_keys (
+    user_id, public_key, sealed_private_key, salt, kdf_params,
+    recovery_sealed_private_key, recovery_salt,
+    failed_attempts, locked_until,
+    failed_recovery_attempts, recovery_locked_until,
+    key_version, created_at, updated_at
+  ) values (
+    p_user_id,
+    decode(p_public_key_b64, 'base64'),
+    decode(p_sealed_private_b64, 'base64'),
+    decode(p_salt_b64, 'base64'),
+    p_kdf_params,
+    case when p_recovery_sealed_b64 is null then null else decode(p_recovery_sealed_b64, 'base64') end,
+    case when p_recovery_salt_b64   is null then null else decode(p_recovery_salt_b64,   'base64') end,
+    0, null, 0, null,
+    1, now(), now()
+  )
+  on conflict (user_id) do update set
+    public_key                  = excluded.public_key,
+    sealed_private_key          = excluded.sealed_private_key,
+    salt                        = excluded.salt,
+    kdf_params                  = excluded.kdf_params,
+    recovery_sealed_private_key = excluded.recovery_sealed_private_key,
+    recovery_salt               = excluded.recovery_salt,
+    failed_attempts             = 0,
+    locked_until                = null,
+    failed_recovery_attempts    = 0,
+    recovery_locked_until       = null,
+    -- Don't bump key_version here — the public key is unchanged.
+    updated_at                  = now();
+end;
+$$;
+
+revoke execute on function public.upsert_user_key(uuid, text, text, text, jsonb, text, text) from public, anon;
+grant  execute on function public.upsert_user_key(uuid, text, text, text, jsonb, text, text) to authenticated;
+
+-- 2) rotate_conv_key — atomically bumps active_key_version and inserts a new
+--    set of bundles. Each bundle may carry recipient_user_id (per-user wrap)
+--    OR recipient_device_id (per-device fallback for peers on the legacy
+--    client). Caller must ensure the new version is strictly greater than
+--    the current one (we lock the row to prevent races).
+
+create or replace function public.rotate_conv_key(
+  p_conv_id        uuid,
+  p_sender_user_id uuid,
+  p_new_version    int,
+  p_bundles        jsonb
+) returns int
+language plpgsql
+security definer
+set search_path = public
+as $$
+declare
+  caller         uuid := auth.uid();
+  cur_version    int;
+  bundle         jsonb;
+  inserted       int := 0;
+  recipient_uid  uuid;
+  recipient_did  uuid;
+  member_user_id uuid;
+  enc_key_hex    text;
+  nonce_hex      text;
+begin
+  if caller is null or caller <> p_sender_user_id then
+    raise exception 'not authenticated as %', p_sender_user_id;
+  end if;
+
+  if not exists (
+    select 1 from public.conversation_members
+     where conversation_id = p_conv_id
+       and user_id         = caller
+       and accepted        = true
+  ) then
+    raise exception 'caller is not an accepted member of %', p_conv_id;
+  end if;
+
+  -- Lock the conversation row so concurrent rotations don't race the version bump.
+  select active_key_version into cur_version
+    from public.conversations
+   where id = p_conv_id
+   for update;
+  if cur_version is null then
+    raise exception 'conversation % not found', p_conv_id;
+  end if;
+  if p_new_version <= cur_version then
+    raise exception 'new key version % must be greater than current %',
+      p_new_version, cur_version;
+  end if;
+
+  update public.conversations
+     set active_key_version = p_new_version
+   where id = p_conv_id;
+
+  -- Insert each bundle. We don't auto-derive recipient_user_id from the
+  -- device anymore — for per-device fallback rows the column stays NULL so
+  -- multiple devices of the same user can each get their own bundle.
+  for bundle in select * from jsonb_array_elements(p_bundles) loop
+    recipient_uid := nullif(bundle->>'recipient_user_id', '')::uuid;
+    recipient_did := nullif(bundle->>'recipient_device_id', '')::uuid;
+    enc_key_hex   := bundle->>'encrypted_key';
+    nonce_hex     := bundle->>'nonce';
+
+    -- Validate membership regardless of mode.
+    if recipient_uid is not null then
+      member_user_id := recipient_uid;
+    elsif recipient_did is not null then
+      select user_id into member_user_id from public.devices where id = recipient_did;
+    else
+      continue;
+    end if;
+    if member_user_id is null then continue; end if;
+    if not exists (
+      select 1 from public.conversation_members
+       where conversation_id = p_conv_id
+         and user_id         = member_user_id
+         and accepted        = true
+    ) then continue; end if;
+
+    insert into public.conversation_keys
+      (conversation_id, recipient_user_id, recipient_device_id,
+       key_version, sender_user_id, sender_device_id,
+       encrypted_key, nonce)
+    values
+      (p_conv_id, recipient_uid, recipient_did,
+       p_new_version, p_sender_user_id, null,
+       decode(enc_key_hex, 'hex'),
+       decode(nonce_hex, 'hex'))
+    on conflict do nothing;
+
+    if found then inserted := inserted + 1; end if;
+  end loop;
+
+  return inserted;
+end;
+$$;
+
+revoke execute on function public.rotate_conv_key(uuid, uuid, int, jsonb) from public, anon;
+grant  execute on function public.rotate_conv_key(uuid, uuid, int, jsonb) to authenticated;