diff --git a/docs/parity/05-calendar.md b/docs/parity/05-calendar.md
index dac38885..a7f5d0a7 100644
--- a/docs/parity/05-calendar.md
+++ b/docs/parity/05-calendar.md
@@ -152,17 +152,17 @@ RN has a solid read path (month/week/agenda, shared-calendar namespacing, per-vi
   - What RN does: plain `Calendar/set` (`src/api/calendar.ts:374-396`). Only matters once RN gains a create-calendar UI; RN has no WebDAV proxy, but it can talk to Stalwart's CalDAV endpoint directly (the same host serves `/dav/`).
   - Fix hint: when adding calendar creation, issue `MKCALENDAR` against the account's calendar-home with `supported-calendar-component-set`, then `Calendar/get` to find the new id.
 
-- [ ] **No first-touch gate: duplicate default calendars on clustered Stalwart (#907)** — `P2` — `bugfix-parity`
+- [x] **No first-touch gate: duplicate default calendars on clustered Stalwart (#907)** — `P2` — `bugfix-parity` — fixed in 58e3ef6 (in-flight dedupe of fetchCalendars/fetchTasks; ensureRange awaits it)
   - What WEB does: `FirstTouchGate` serialises the first `Calendar/*`/`CalendarEvent/*` request per account so concurrent first-touch requests cannot each create a default calendar (ref `lib/jmap/first-touch-gate.ts:56-101`, `lib/jmap/client.ts:678, 1129`, changelog 1.9.0 #907).
   - What RN does: `CalendarScreen` fires `fetchCalendars()` on mount and, in a second effect, `ensureRange()` which sees `calendars.length === 0` and calls `fetchCalendars()` again then `CalendarEvent/query` (`src/screens/CalendarScreen.tsx:261-269`, `src/stores/calendar-store.ts:235-251`); `auth-store` also kicks `fetchCalendars`/`refresh` after login (`src/stores/auth-store.ts:92-98`). Two to three concurrent first-touch calls — exactly the #907 race. RN affected.
   - Fix hint: port `FirstTouchGate` into `src/api/jmap-client.ts` `request()`, or at minimum dedupe in-flight `fetchCalendars` and make `ensureRange` await the mount fetch.
 
-- [ ] **Tasks-only calendar detection misses CalDAV tasks without `@type`** — `P2` — `bugfix-parity`
+- [x] **Tasks-only calendar detection misses CalDAV tasks without `@type`** — `P2` — `bugfix-parity` — fixed in 58e3ef6
   - What WEB does: `isTaskLikeObject` treats `@type: Task` OR presence of `due`/`progress`/`percentComplete` (and `@type !== 'Event'`) as a task, both for the tasks list and for hiding tasks-only calendars (ref `lib/calendar-component-detection.ts:30-58`, `lib/jmap/client.ts:6300-6316`, changelog 1.5.x #84 "Detect tasks created by external CalDAV clients such as Thunderbird").
   - What RN does: `fetchEvents` classifies solely on `'@type' === 'Task'` (`src/stores/calendar-store.ts:208-227`); Thunderbird/Todoist VTODOs that Stalwart returns without `@type` are neither shown as tasks nor counted for `taskOnlyCalendarIds` (they fall through as start-less "events" and are dropped by `!!e.start`).
   - Fix hint: port `isTaskLikeObject` and use it in both filters.
 
-- [ ] **Shared accounts without calendar access are re-probed on every fetch** — `P3` — `bugfix-parity`
+- [x] **Shared accounts without calendar access are re-probed on every fetch** — `P3` — `bugfix-parity` — fixed in 58e3ef6
   - What WEB does: remembers `forbidden`/`accountNotFound` per account in `calendarAccessDenied` and skips it (ref `lib/jmap/client.ts:5806-5813`, changelog 1.8.1 "Stop re-probing shared accounts that have no calendar access").
   - What RN does: `getCalendars` and `fetchEvents` try every calendar-capable session account each time and swallow errors (`src/api/calendar.ts:140-186`, `src/stores/calendar-store.ts:194-204`).
   - Fix hint: keep a module-level `Set` of denied account ids, reset on reconnect.
@@ -226,7 +226,7 @@ RN has a solid read path (month/week/agenda, shared-calendar namespacing, per-vi
 
 ### Data loading / sync
 
-- [ ] **Range queries fetch every event in the account (no `after`/`before`), capped at 1000** — `P2` — `bug`
+- [x] **Range queries fetch every event in the account (no `after`/`before`), capped at 1000** — `P2` — `bug` — fixed in 58e3ef6
   - What WEB does: `CalendarEvent/query` with `{ after, before }` + `timeZone` (changelog 1.7.0 "timezone-aware calendar queries", 1.7.1 "Stalwart-compatible calendar filters") (ref `lib/jmap/client.ts:5722-5745`).
   - What RN does: `queryEvents` ignores its `_after`/`_before` arguments citing "Stalwart rejects after/before filters" (outdated) and uses `limit: 1000` (`src/api/calendar.ts:188-208`); `fetchEvents` then re-fetches everything whenever `ensureRange` widens the union (`src/stores/calendar-store.ts:235-251`). Accounts with more than 1000 objects silently lose events; every navigation past the loaded range re-downloads all events.
   - Fix hint: send `filter: { after, before, inCalendar... }` as WEB does (`{ operator: 'AND', conditions: [...] }` when combined), keep `timeZone`; then `loadedRange` can be the requested window rather than a growing union.
@@ -246,7 +246,7 @@ RN has a solid read path (month/week/agenda, shared-calendar namespacing, per-vi
   - What RN does: `fetch(url)` from the phone (`src/stores/calendar-subscriptions-store.ts:42-53`). No server is exposed, so the SSRF class does not apply; the device can be pointed at LAN hosts, which is the user's own network. Redirects are followed by `fetch` without validation (fine). N/A for the advisory; worth a 10 MB size cap and a `text/calendar`-ish content check (already checks `BEGIN:VCALENDAR`).
   - Fix hint: optional size cap.
 
-- [ ] **Created recurring event appears as a single instance until refresh; created event lacks `utcStart`/`utcEnd`** — `P3` — `partial`
+- [x] **Created recurring event appears as a single instance until refresh; created event lacks `utcStart`/`utcEnd`** — `P3` — `partial` — fixed in 58e3ef6
   - What WEB does: `createCalendarEvent` refetches the created event with full properties (`lib/jmap/client.ts:5942-5960`) and the store refetches when occurrences are in view.
   - What RN does: `createEvent` merges the `/set` echo over the payload (`src/api/calendar.ts:272-274`) and appends without expansion (`src/stores/calendar-store.ts:286-304`).
   - Fix hint: after create, `CalendarEvent/get` the id (RN `getEvents([id])`) and, if `recurrenceRules` is set, run `expandRecurringEvents` for `loadedRange` or call `refresh()`.
diff --git a/src/api/calendar.ts b/src/api/calendar.ts
index 02b19417..f279305b 100644
--- a/src/api/calendar.ts
+++ b/src/api/calendar.ts
@@ -1,6 +1,6 @@
 import { jmapClient } from './jmap-client';
 import { CAPABILITIES } from './types';
-import type { Calendar, CalendarEvent } from './types';
+import type { Calendar, CalendarEvent, CalendarRights } from './types';
 import { getEffectiveTimeZone } from '../lib/calendar-timezone';
 import { SCAN_PROPERTIES, type ScannedCalendarObject } from '../lib/calendar-component-detection';
 
@@ -489,12 +489,15 @@ export async function parseCalendarBlob(blobId: string): Promise<Partial<Calenda
 export async function createCalendar(
   name: string,
   color?: string,
+  description?: string,
 ): Promise<Calendar> {
   const accountId = jmapClient.accountId;
+  const props: Record<string, unknown> = { name, color, isVisible: true, isSubscribed: true };
+  if (description?.trim()) props.description = description.trim();
   const res = await jmapClient.request(
     [['Calendar/set', {
       accountId,
-      create: { 'new-cal': { name, color, isVisible: true, isSubscribed: true } },
+      create: { 'new-cal': props },
     }, '0']],
     USING,
   );
@@ -527,12 +530,119 @@ export async function setDefaultCalendar(
   methodResult(res);
 }
 
-// Destroy a calendar. `onDestroyEvents: 'destroy'` removes its events too —
+// Destroy a calendar. `onDestroyRemoveEvents` removes its events too —
 // Stalwart otherwise refuses to delete a non-empty calendar.
-export async function deleteCalendar(id: string): Promise<void> {
-  const accountId = jmapClient.accountId;
-  await jmapClient.request(
+export async function deleteCalendar(id: string, targetAccountId?: string): Promise<void> {
+  const accountId = targetAccountId || jmapClient.accountId;
+  const res = await jmapClient.request(
     [['Calendar/set', { accountId, destroy: [id], onDestroyRemoveEvents: true }, '0']],
     USING,
   );
+  const result = methodResult<{ notDestroyed?: Record<string, { description?: string; type?: string }> }>(res);
+  const err = result.notDestroyed?.[id];
+  if (err) throw new Error(err.description || err.type || 'Failed to delete calendar');
+}
+
+export interface CalendarUpdates {
+  name?: string;
+  color?: string | null;
+  description?: string | null;
+  sortOrder?: number;
+  isSubscribed?: boolean;
+}
+
+// Rename / recolour / describe a calendar (Calendar/set update).
+export async function updateCalendar(
+  id: string,
+  updates: CalendarUpdates,
+  targetAccountId?: string,
+): Promise<void> {
+  const accountId = targetAccountId || jmapClient.accountId;
+  const res = await jmapClient.request(
+    [['Calendar/set', { accountId, update: { [id]: updates } }, '0']],
+    USING,
+  );
+  const result = methodResult<{ notUpdated?: Record<string, { description?: string; type?: string }> }>(res);
+  const err = result.notUpdated?.[id];
+  if (err) throw new Error(err.description || err.type || 'Failed to update calendar');
+}
+
+// Add, update, or remove a principal's rights on an owned calendar via a
+// `shareWith/{principalId}` patch (null removes the share).
+export async function setCalendarShare(
+  calendarId: string,
+  principalId: string,
+  rights: CalendarRights | null,
+  targetAccountId?: string,
+): Promise<void> {
+  const accountId = targetAccountId || jmapClient.accountId;
+  const res = await jmapClient.request(
+    [['Calendar/set', {
+      accountId,
+      update: { [calendarId]: { [`shareWith/${principalId}`]: rights } },
+    }, '0']],
+    USING,
+  );
+  const result = methodResult<{ notUpdated?: Record<string, { description?: string; type?: string }> }>(res);
+  const err = result.notUpdated?.[calendarId];
+  if (err) throw new Error(err.description || err.type || 'Failed to update sharing');
+}
+
+/**
+ * Remove every event from a calendar. Events that live ONLY in this calendar
+ * are destroyed; events also linked to another calendar are unlinked instead
+ * (their `calendarIds` loses this calendar) so the user's copy elsewhere is
+ * not cascade-deleted. Returns the number of events removed.
+ */
+export async function clearCalendarEvents(
+  calendarId: string,
+  targetAccountId?: string,
+): Promise<number> {
+  const accountId = targetAccountId || jmapClient.accountId;
+  let removed = 0;
+  // Loop for accounts with more than one query page of objects.
+  for (let pass = 0; pass < 20; pass++) {
+    const ids = await queryEvents([calendarId], '', '', accountId);
+    if (ids.length === 0) break;
+    const batchSize = jmapClient.getMaxObjectsInGet();
+    const objects: Array<{ id: string; calendarIds?: Record<string, boolean> }> = [];
+    for (let i = 0; i < ids.length; i += batchSize) {
+      const res = await jmapClient.request(
+        [['CalendarEvent/get', {
+          accountId,
+          ids: ids.slice(i, i + batchSize),
+          properties: ['id', 'calendarIds'],
+        }, '0']],
+        USING,
+      );
+      objects.push(...(methodResult<{ list: typeof objects }>(res).list ?? []));
+    }
+    const toDestroy: string[] = [];
+    const toUnlink: Array<{ id: string; calendarIds: Record<string, boolean> }> = [];
+    for (const obj of objects) {
+      const others = { ...(obj.calendarIds || {}) };
+      delete others[calendarId];
+      if (Object.keys(others).length === 0) toDestroy.push(obj.id);
+      else toUnlink.push({ id: obj.id, calendarIds: others });
+    }
+    if (toDestroy.length > 0) {
+      const res = await jmapClient.request(
+        [['CalendarEvent/set', { accountId, destroy: toDestroy }, '0']],
+        USING,
+      );
+      removed += (methodResult<{ destroyed?: string[] }>(res).destroyed ?? []).length;
+    }
+    if (toUnlink.length > 0) {
+      const update: Record<string, unknown> = {};
+      for (const { id, calendarIds } of toUnlink) update[id] = { calendarIds };
+      const res = await jmapClient.request(
+        [['CalendarEvent/set', { accountId, update }, '0']],
+        USING,
+      );
+      removed += Object.keys(methodResult<{ updated?: Record<string, unknown> }>(res).updated ?? {}).length;
+    }
+    if (toDestroy.length === 0 && toUnlink.length === 0) break;
+    if (ids.length < 1000) break;
+  }
+  return removed;
 }
diff --git a/src/api/types.ts b/src/api/types.ts
index f03cb741..6cd2b96c 100644
--- a/src/api/types.ts
+++ b/src/api/types.ts
@@ -544,6 +544,8 @@ export interface Calendar {
   isDefault?: boolean;
   sortOrder?: number;
   myRights?: CalendarRights;
+  // Principals this (owned) calendar is shared with and their rights.
+  shareWith?: Record<string, CalendarRights> | null;
   // Client-only: JMAP account the calendar was fetched from. Absent for the
   // primary account; set for calendars shared with the user.
   accountId?: string;
diff --git a/src/components/calendar/CalendarEditSheet.tsx b/src/components/calendar/CalendarEditSheet.tsx
new file mode 100644
index 00000000..571f5c23
--- /dev/null
+++ b/src/components/calendar/CalendarEditSheet.tsx
@@ -0,0 +1,182 @@
+import React from 'react';
+import {
+  ActivityIndicator,
+  Modal,
+  Pressable,
+  ScrollView,
+  StyleSheet,
+  Text,
+  TextInput,
+  TouchableWithoutFeedback,
+  View,
+} from 'react-native';
+import { Check } from 'lucide-react-native';
+import type { Calendar } from '../../api/types';
+import { radius, spacing, typography, type ThemePalette } from '../../theme/tokens';
+import { useColors } from '../../theme/colors';
+import { useLocaleStore } from '../../stores/locale-store';
+import { CALENDAR_COLOR_PALETTE, getCalendarColor } from '../../lib/calendar-utils';
+import Button from '../Button';
+
+export interface CalendarEditValues {
+  name: string;
+  color: string;
+  description: string;
+}
+
+interface CalendarEditSheetProps {
+  visible: boolean;
+  // Existing calendar to edit; null creates a new one.
+  calendar: Calendar | null;
+  onSave: (values: CalendarEditValues) => Promise<void>;
+  onClose: () => void;
+}
+
+// Create / rename / recolour / describe a calendar. The same fields the
+// webmail's calendar-management settings offer, as a bottom sheet.
+export function CalendarEditSheet({ visible, calendar, onSave, onClose }: CalendarEditSheetProps) {
+  const c = useColors();
+  const styles = React.useMemo(() => makeStyles(c), [c]);
+  const t = useLocaleStore((s) => s.t);
+  const [name, setName] = React.useState('');
+  const [color, setColor] = React.useState<string>(CALENDAR_COLOR_PALETTE[0]);
+  const [description, setDescription] = React.useState('');
+  const [saving, setSaving] = React.useState(false);
+  const [error, setError] = React.useState<string | null>(null);
+
+  React.useEffect(() => {
+    if (!visible) return;
+    setName(calendar?.name ?? '');
+    setColor(calendar ? getCalendarColor(calendar) : CALENDAR_COLOR_PALETTE[0]);
+    setDescription(calendar?.description ?? '');
+    setError(null);
+    setSaving(false);
+  }, [visible, calendar]);
+
+  const handleSave = async () => {
+    const trimmed = name.trim();
+    if (!trimmed || saving) return;
+    setSaving(true);
+    setError(null);
+    try {
+      await onSave({ name: trimmed, color, description: description.trim() });
+      onClose();
+    } catch (e) {
+      setError(e instanceof Error ? e.message : t('calendar.notifications.event_error', 'Something went wrong'));
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  return (
+    <Modal visible={visible} transparent animationType="slide" onRequestClose={onClose}>
+      <TouchableWithoutFeedback onPress={onClose}>
+        <View style={styles.backdrop}>
+          <TouchableWithoutFeedback>
+            <View style={styles.sheet}>
+              <Text style={styles.title}>
+                {calendar
+                  ? t('calendar.management.edit_calendar', 'Edit calendar')
+                  : t('calendar.management.new_calendar', 'New calendar')}
+              </Text>
+              <ScrollView keyboardShouldPersistTaps="handled" contentContainerStyle={styles.body}>
+                <Text style={styles.label}>{t('calendar.management.name', 'Name')}</Text>
+                <TextInput
+                  value={name}
+                  onChangeText={setName}
+                  placeholder={t('calendar.management.name_placeholder', 'Calendar name')}
+                  placeholderTextColor={c.textMuted}
+                  style={styles.input}
+                  autoFocus
+                />
+                <Text style={styles.label}>{t('calendar.management.color', 'Color')}</Text>
+                <View style={styles.paletteRow}>
+                  {CALENDAR_COLOR_PALETTE.map((col) => {
+                    const active = color.toLowerCase() === col.toLowerCase();
+                    return (
+                      <Pressable
+                        key={col}
+                        onPress={() => setColor(col)}
+                        style={[styles.swatch, { backgroundColor: col }, active && styles.swatchActive]}
+                      >
+                        {active && <Check size={12} color={c.textInverse} />}
+                      </Pressable>
+                    );
+                  })}
+                </View>
+                <Text style={styles.label}>{t('calendar.management.description', 'Description')}</Text>
+                <TextInput
+                  value={description}
+                  onChangeText={setDescription}
+                  placeholder={t('calendar.management.description_placeholder', 'Optional')}
+                  placeholderTextColor={c.textMuted}
+                  style={[styles.input, styles.multiline]}
+                  multiline
+                />
+                {error ? <Text style={styles.error}>{error}</Text> : null}
+              </ScrollView>
+              <View style={styles.footer}>
+                <Button variant="outline" size="sm" onPress={onClose}>
+                  {t('common.cancel', 'Cancel')}
+                </Button>
+                <Button
+                  size="sm"
+                  onPress={() => { void handleSave(); }}
+                  disabled={!name.trim() || saving}
+                  icon={saving ? <ActivityIndicator size="small" color={c.primaryForeground} /> : undefined}
+                >
+                  {calendar ? t('common.save', 'Save') : t('common.create', 'Create')}
+                </Button>
+              </View>
+            </View>
+          </TouchableWithoutFeedback>
+        </View>
+      </TouchableWithoutFeedback>
+    </Modal>
+  );
+}
+
+function makeStyles(c: ThemePalette) {
+  return StyleSheet.create({
+    backdrop: {
+      flex: 1,
+      backgroundColor: 'rgba(0,0,0,0.5)',
+      justifyContent: 'flex-end',
+    },
+    sheet: {
+      backgroundColor: c.background,
+      borderTopLeftRadius: radius.xl,
+      borderTopRightRadius: radius.xl,
+      padding: spacing.lg,
+      paddingBottom: spacing.xxl,
+      maxHeight: '85%',
+      gap: spacing.md,
+    },
+    title: { ...typography.h3, color: c.text },
+    body: { gap: spacing.sm },
+    label: { ...typography.captionMedium, color: c.textSecondary, marginTop: spacing.xs },
+    input: {
+      minHeight: 40,
+      borderWidth: 1,
+      borderColor: c.border,
+      borderRadius: radius.sm,
+      paddingHorizontal: spacing.md,
+      paddingVertical: spacing.sm,
+      color: c.text,
+      backgroundColor: c.surface,
+      ...typography.body,
+    },
+    multiline: { minHeight: 64, textAlignVertical: 'top' },
+    paletteRow: { flexDirection: 'row', flexWrap: 'wrap', gap: spacing.sm },
+    swatch: {
+      width: 28,
+      height: 28,
+      borderRadius: radius.full,
+      alignItems: 'center',
+      justifyContent: 'center',
+    },
+    swatchActive: { borderWidth: 2, borderColor: c.text },
+    error: { ...typography.caption, color: c.error },
+    footer: { flexDirection: 'row', justifyContent: 'flex-end', gap: spacing.md },
+  });
+}
diff --git a/src/components/calendar/CalendarShareSheet.tsx b/src/components/calendar/CalendarShareSheet.tsx
new file mode 100644
index 00000000..8262d471
--- /dev/null
+++ b/src/components/calendar/CalendarShareSheet.tsx
@@ -0,0 +1,323 @@
+import React from 'react';
+import {
+  ActivityIndicator,
+  Alert,
+  Modal,
+  Pressable,
+  ScrollView,
+  StyleSheet,
+  Text,
+  TextInput,
+  TouchableWithoutFeedback,
+  View,
+} from 'react-native';
+import { Trash2, UserPlus, Users } from 'lucide-react-native';
+import { getPrincipals, ownPrincipalId } from '../../api/files';
+import type { Calendar, CalendarRights, Principal } from '../../api/types';
+import { spacing, radius, typography, type ThemePalette } from '../../theme/tokens';
+import { useColors } from '../../theme/colors';
+import { useLocaleStore } from '../../stores/locale-store';
+
+type RolePreset = 'freeBusy' | 'read' | 'readWrite' | 'manager';
+
+// Same presets the webmail's share-collection dialog offers for calendars.
+const CALENDAR_PRESETS: Record<RolePreset, CalendarRights> = {
+  freeBusy: {
+    mayReadFreeBusy: true, mayReadItems: false, mayWriteAll: false, mayWriteOwn: false,
+    mayUpdatePrivate: false, mayRSVP: false, mayShare: false, mayDelete: false,
+  },
+  read: {
+    mayReadFreeBusy: true, mayReadItems: true, mayWriteAll: false, mayWriteOwn: false,
+    mayUpdatePrivate: false, mayRSVP: false, mayShare: false, mayDelete: false,
+  },
+  readWrite: {
+    mayReadFreeBusy: true, mayReadItems: true, mayWriteAll: true, mayWriteOwn: true,
+    mayUpdatePrivate: true, mayRSVP: true, mayShare: false, mayDelete: false,
+  },
+  manager: {
+    mayReadFreeBusy: true, mayReadItems: true, mayWriteAll: true, mayWriteOwn: true,
+    mayUpdatePrivate: true, mayRSVP: true, mayShare: true, mayDelete: true,
+  },
+};
+
+const PRESET_LABEL_KEYS: Record<RolePreset, [string, string]> = {
+  freeBusy: ['calendar.share.role_free_busy', 'Free/busy'],
+  read: ['calendar.share.role_viewer', 'Viewer'],
+  readWrite: ['calendar.share.role_editor', 'Editor'],
+  manager: ['calendar.share.role_manager', 'Manager'],
+};
+
+const PRESET_ORDER: RolePreset[] = ['freeBusy', 'read', 'readWrite', 'manager'];
+
+function detectPreset(rights: CalendarRights): RolePreset | 'custom' {
+  for (const preset of PRESET_ORDER) {
+    const expected = CALENDAR_PRESETS[preset];
+    const keys = Object.keys(expected) as (keyof CalendarRights)[];
+    if (keys.every((k) => !!expected[k] === !!rights[k])) return preset;
+  }
+  return 'custom';
+}
+
+interface CalendarShareSheetProps {
+  calendar: Calendar | null;
+  onShare: (calendarId: string, principalId: string, rights: CalendarRights | null) => Promise<void>;
+  onClose: () => void;
+}
+
+// JMAP sharing for an owned calendar: pick a principal, choose a role. The
+// principal list comes from the same Principal/query the Files share sheet
+// uses.
+export function CalendarShareSheet({ calendar, onShare, onClose }: CalendarShareSheetProps) {
+  const c = useColors();
+  const styles = React.useMemo(() => makeStyles(c), [c]);
+  const t = useLocaleStore((s) => s.t);
+
+  const [principals, setPrincipals] = React.useState<Principal[]>([]);
+  const [loading, setLoading] = React.useState(false);
+  const [shares, setShares] = React.useState<Record<string, CalendarRights>>({});
+  const [search, setSearch] = React.useState('');
+  const [savingId, setSavingId] = React.useState<string | null>(null);
+
+  React.useEffect(() => {
+    if (!calendar) return;
+    setShares(calendar.shareWith ?? {});
+    setSearch('');
+    setLoading(true);
+    getPrincipals()
+      .then(setPrincipals)
+      .catch(() => setPrincipals([]))
+      .finally(() => setLoading(false));
+  }, [calendar]);
+
+  const principalsById = React.useMemo(() => {
+    const map = new Map<string, Principal>();
+    for (const p of principals) map.set(p.id, p);
+    return map;
+  }, [principals]);
+
+  const sharedEntries = React.useMemo(
+    () => Object.entries(shares).filter(([, rights]) => rights != null),
+    [shares],
+  );
+
+  const candidates = React.useMemo(() => {
+    const self = ownPrincipalId();
+    const q = search.trim().toLowerCase();
+    return principals
+      .filter((p) => p.id !== self && shares[p.id] == null)
+      .filter((p) =>
+        !q ||
+        p.name?.toLowerCase().includes(q) ||
+        p.email?.toLowerCase().includes(q) ||
+        p.description?.toLowerCase().includes(q))
+      .slice(0, 25);
+  }, [principals, shares, search]);
+
+  const applyShare = async (principalId: string, rights: CalendarRights | null) => {
+    if (!calendar || savingId) return;
+    setSavingId(principalId);
+    try {
+      await onShare(calendar.id, principalId, rights);
+      setShares((prev) => {
+        const next = { ...prev };
+        if (rights == null) delete next[principalId];
+        else next[principalId] = rights;
+        return next;
+      });
+    } catch (e) {
+      Alert.alert(
+        t('calendar.share.error', 'Failed to update sharing'),
+        e instanceof Error ? e.message : String(e),
+      );
+    } finally {
+      setSavingId(null);
+    }
+  };
+
+  if (!calendar) return null;
+
+  const renderPrincipalLabel = (principalId: string) => {
+    const p = principalsById.get(principalId);
+    return (
+      <View style={styles.principalInfo}>
+        <Text style={styles.principalName} numberOfLines={1}>
+          {p?.description || p?.name || principalId}
+        </Text>
+        {p?.email ? (
+          <Text style={styles.principalEmail} numberOfLines={1}>{p.email}</Text>
+        ) : null}
+      </View>
+    );
+  };
+
+  return (
+    <Modal visible transparent animationType="slide" onRequestClose={onClose}>
+      <TouchableWithoutFeedback onPress={onClose}>
+        <View style={styles.backdrop}>
+          <TouchableWithoutFeedback>
+            <View style={styles.sheet}>
+              <View style={styles.titleRow}>
+                <Users size={18} color={c.textMuted} />
+                <Text style={styles.title} numberOfLines={1}>
+                  {t('calendar.share.title', 'Share')} “{calendar.name}”
+                </Text>
+              </View>
+
+              <ScrollView style={styles.scroll} keyboardShouldPersistTaps="handled">
+                {sharedEntries.length > 0 ? (
+                  <View style={styles.section}>
+                    <Text style={styles.sectionLabel}>{t('calendar.share.shared_with', 'Shared with')}</Text>
+                    {sharedEntries.map(([principalId, rights]) => {
+                      const preset = detectPreset(rights);
+                      const busy = savingId === principalId;
+                      return (
+                        <View key={principalId} style={styles.shareRow}>
+                          {renderPrincipalLabel(principalId)}
+                          <View style={styles.roleChips}>
+                            {PRESET_ORDER.map((p) => (
+                              <Pressable
+                                key={p}
+                                onPress={() => void applyShare(principalId, CALENDAR_PRESETS[p])}
+                                disabled={busy}
+                                style={[styles.chip, preset === p && styles.chipActive]}
+                              >
+                                <Text style={[styles.chipText, preset === p && styles.chipTextActive]}>
+                                  {t(PRESET_LABEL_KEYS[p][0], PRESET_LABEL_KEYS[p][1])}
+                                </Text>
+                              </Pressable>
+                            ))}
+                            {preset === 'custom' ? (
+                              <Text style={styles.customLabel}>{t('calendar.share.role_custom', 'Custom')}</Text>
+                            ) : null}
+                            <Pressable
+                              onPress={() => void applyShare(principalId, null)}
+                              disabled={busy}
+                              hitSlop={8}
+                              style={styles.removeBtn}
+                            >
+                              {busy ? (
+                                <ActivityIndicator size="small" color={c.textMuted} />
+                              ) : (
+                                <Trash2 size={16} color={c.error} />
+                              )}
+                            </Pressable>
+                          </View>
+                        </View>
+                      );
+                    })}
+                  </View>
+                ) : null}
+
+                <View style={styles.section}>
+                  <Text style={styles.sectionLabel}>{t('calendar.share.add_people', 'Add people')}</Text>
+                  <TextInput
+                    value={search}
+                    onChangeText={setSearch}
+                    placeholder={t('calendar.share.search_placeholder', 'Search by name or email')}
+                    placeholderTextColor={c.textMuted}
+                    autoCapitalize="none"
+                    autoCorrect={false}
+                    style={styles.input}
+                  />
+                  {loading ? (
+                    <ActivityIndicator size="small" color={c.textMuted} style={{ marginTop: spacing.md }} />
+                  ) : candidates.length === 0 ? (
+                    <Text style={styles.empty}>
+                      {principals.length === 0
+                        ? t('calendar.share.no_principals', 'Sharing is not available on this server.')
+                        : t('calendar.share.no_matches', 'No matches')}
+                    </Text>
+                  ) : (
+                    candidates.map((p) => (
+                      <Pressable
+                        key={p.id}
+                        onPress={() => void applyShare(p.id, CALENDAR_PRESETS.read)}
+                        disabled={!!savingId}
+                        style={({ pressed }) => [styles.candidateRow, pressed && styles.rowPressed]}
+                      >
+                        {renderPrincipalLabel(p.id)}
+                        {savingId === p.id ? (
+                          <ActivityIndicator size="small" color={c.textMuted} />
+                        ) : (
+                          <UserPlus size={18} color={c.primary} />
+                        )}
+                      </Pressable>
+                    ))
+                  )}
+                </View>
+              </ScrollView>
+
+              <Pressable onPress={onClose} style={styles.doneBtn}>
+                <Text style={styles.doneText}>{t('common.done', 'Done')}</Text>
+              </Pressable>
+            </View>
+          </TouchableWithoutFeedback>
+        </View>
+      </TouchableWithoutFeedback>
+    </Modal>
+  );
+}
+
+function makeStyles(c: ThemePalette) {
+  return StyleSheet.create({
+    backdrop: { flex: 1, backgroundColor: 'rgba(0,0,0,0.5)', justifyContent: 'flex-end' },
+    sheet: {
+      backgroundColor: c.background,
+      borderTopLeftRadius: radius.xl,
+      borderTopRightRadius: radius.xl,
+      padding: spacing.lg,
+      paddingBottom: spacing.xxl,
+      maxHeight: '85%',
+    },
+    titleRow: { flexDirection: 'row', alignItems: 'center', gap: spacing.sm, marginBottom: spacing.md },
+    title: { ...typography.h3, color: c.text, flex: 1 },
+    scroll: { flexGrow: 0 },
+    section: { marginBottom: spacing.lg, gap: spacing.sm },
+    sectionLabel: { ...typography.captionMedium, color: c.textSecondary },
+    shareRow: {
+      gap: spacing.xs,
+      paddingVertical: spacing.sm,
+      borderBottomWidth: 1,
+      borderBottomColor: c.borderLight,
+    },
+    principalInfo: { flex: 1, minWidth: 0 },
+    principalName: { ...typography.body, color: c.text },
+    principalEmail: { ...typography.caption, color: c.textMuted },
+    roleChips: { flexDirection: 'row', flexWrap: 'wrap', alignItems: 'center', gap: spacing.xs },
+    chip: {
+      paddingHorizontal: spacing.sm,
+      paddingVertical: 4,
+      borderRadius: radius.full,
+      borderWidth: 1,
+      borderColor: c.border,
+      backgroundColor: c.surface,
+    },
+    chipActive: { backgroundColor: c.primary, borderColor: c.primary },
+    chipText: { ...typography.caption, color: c.text },
+    chipTextActive: { color: c.primaryForeground },
+    customLabel: { ...typography.caption, color: c.textMuted },
+    removeBtn: { marginLeft: 'auto', padding: 4 },
+    input: {
+      minHeight: 40,
+      borderWidth: 1,
+      borderColor: c.border,
+      borderRadius: radius.sm,
+      paddingHorizontal: spacing.md,
+      color: c.text,
+      backgroundColor: c.surface,
+      ...typography.body,
+    },
+    empty: { ...typography.caption, color: c.textMuted, paddingVertical: spacing.sm },
+    candidateRow: {
+      flexDirection: 'row',
+      alignItems: 'center',
+      gap: spacing.md,
+      paddingVertical: spacing.sm,
+      borderBottomWidth: 1,
+      borderBottomColor: c.borderLight,
+    },
+    rowPressed: { backgroundColor: c.surfaceHover },
+    doneBtn: { alignSelf: 'flex-end', paddingVertical: spacing.sm, paddingHorizontal: spacing.md },
+    doneText: { ...typography.bodyMedium, color: c.primary },
+  });
+}
diff --git a/src/components/calendar/CalendarSidebarDrawer.tsx b/src/components/calendar/CalendarSidebarDrawer.tsx
index ed0175b8..0077b00e 100644
--- a/src/components/calendar/CalendarSidebarDrawer.tsx
+++ b/src/components/calendar/CalendarSidebarDrawer.tsx
@@ -11,7 +11,9 @@ import {
   View,
 } from 'react-native';
 import { SafeAreaView } from 'react-native-safe-area-context';
-import { Check, X, Upload, Rss, Shuffle, Star } from 'lucide-react-native';
+import {
+  Check, X, Upload, Rss, Shuffle, Star, Plus, Pencil, Share2, Eraser, Trash2,
+} from 'lucide-react-native';
 import type { Calendar } from '../../api/types';
 import { radius, spacing, typography, type ThemePalette } from '../../theme/tokens';
 import { useColors } from '../../theme/colors';
@@ -28,11 +30,19 @@ interface CalendarSidebarDrawerProps {
   onClose: () => void;
   onImport?: () => void;
   onManageSubscriptions?: () => void;
-  // Long-press actions. Set-default applies to the user's own calendars;
-  // color change/reset applies to shared calendars (per-viewer recolor).
+  onCreate?: () => void;
+  // Long-press actions. Set-default / rename / share / clear / delete apply
+  // to the user's own calendars; color change applies to own calendars
+  // (server-side) and shared calendars (per-viewer recolor).
   onSetDefault?: (calendar: Calendar) => void;
   onSetColor?: (calendar: Calendar, color: string) => void;
   onResetColor?: (calendar: Calendar) => void;
+  onRename?: (calendar: Calendar) => void;
+  onShare?: (calendar: Calendar) => void;
+  onClear?: (calendar: Calendar) => void;
+  onDelete?: (calendar: Calendar) => void;
+  // Client-side iCal subscriptions are managed from the subscriptions sheet.
+  isSubscriptionCalendar?: (calendarId: string) => boolean;
 }
 
 export function CalendarSidebarDrawer({
@@ -43,9 +53,15 @@ export function CalendarSidebarDrawer({
   onClose,
   onImport,
   onManageSubscriptions,
+  onCreate,
   onSetDefault,
   onSetColor,
   onResetColor,
+  onRename,
+  onShare,
+  onClear,
+  onDelete,
+  isSubscriptionCalendar,
 }: CalendarSidebarDrawerProps) {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
@@ -102,6 +118,11 @@ export function CalendarSidebarDrawer({
     onSetDefault,
     onSetColor,
     onResetColor,
+    onRename,
+    onShare,
+    onClear,
+    onDelete,
+    isSubscriptionCalendar,
   };
 
   return (
@@ -144,8 +165,17 @@ export function CalendarSidebarDrawer({
               <Section title="Subscribed" calendars={subscribed} {...sectionProps} />
             )}
 
-            {(onImport || onManageSubscriptions) && (
+            {(onImport || onManageSubscriptions || onCreate) && (
               <View style={styles.actionsSection}>
+                {onCreate && (
+                  <Pressable
+                    onPress={onCreate}
+                    style={({ pressed }) => [styles.actionRow, pressed && styles.rowPressed]}
+                  >
+                    <Plus size={18} color={c.textSecondary} />
+                    <Text style={styles.actionText}>New calendar</Text>
+                  </Pressable>
+                )}
                 {onManageSubscriptions && (
                   <Pressable
                     onPress={onManageSubscriptions}
@@ -183,6 +213,11 @@ function Section({
   onSetDefault,
   onSetColor,
   onResetColor,
+  onRename,
+  onShare,
+  onClear,
+  onDelete,
+  isSubscriptionCalendar,
 }: {
   title: string;
   calendars: Calendar[];
@@ -193,6 +228,11 @@ function Section({
   onSetDefault?: (calendar: Calendar) => void;
   onSetColor?: (calendar: Calendar, color: string) => void;
   onResetColor?: (calendar: Calendar) => void;
+  onRename?: (calendar: Calendar) => void;
+  onShare?: (calendar: Calendar) => void;
+  onClear?: (calendar: Calendar) => void;
+  onDelete?: (calendar: Calendar) => void;
+  isSubscriptionCalendar?: (calendarId: string) => boolean;
 }) {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
@@ -202,9 +242,17 @@ function Section({
       {calendars.map((cal) => {
         const visible = !hiddenSet.has(cal.id);
         const isBirthday = cal.id === BIRTHDAY_CALENDAR_ID;
-        const canSetDefault = !!onSetDefault && !cal.isShared && !isBirthday && !cal.isDefault;
-        const canRecolor = !!onSetColor && !!cal.isShared;
-        const hasActions = canSetDefault || canRecolor;
+        const isSubscription = !!isSubscriptionCalendar?.(cal.id);
+        const isOwn = !cal.isShared && !isBirthday && !isSubscription;
+        const canSetDefault = !!onSetDefault && isOwn && !cal.isDefault;
+        // Own calendars recolour server-side; shared ones locally (#345).
+        const canRecolor = !!onSetColor && (!!cal.isShared || isOwn);
+        const canRename = !!onRename && isOwn;
+        const canShare = !!onShare && isOwn && (!cal.myRights || cal.myRights.mayShare !== false);
+        const canClear = !!onClear && isOwn && isWritableCalendar(cal);
+        // Like webmail: the default calendar and shared calendars can't be deleted.
+        const canDelete = !!onDelete && isOwn && !cal.isDefault && (!cal.myRights || cal.myRights.mayDelete !== false);
+        const hasActions = canSetDefault || canRecolor || canRename || canShare || canClear || canDelete;
         const expanded = expandedId === cal.id && hasActions;
         return (
           <View key={cal.id}>
@@ -246,6 +294,15 @@ function Section({
                     <Text style={styles.panelRowText}>Set as default calendar</Text>
                   </Pressable>
                 )}
+                {canRename && (
+                  <Pressable
+                    onPress={() => { onExpand(null); onRename!(cal); }}
+                    style={({ pressed }) => [styles.panelRow, pressed && styles.rowPressed]}
+                  >
+                    <Pencil size={16} color={c.textSecondary} />
+                    <Text style={styles.panelRowText}>Edit name and description</Text>
+                  </Pressable>
+                )}
                 {canRecolor && (
                   <>
                     <View style={styles.paletteRow}>
@@ -266,7 +323,7 @@ function Section({
                         );
                       })}
                     </View>
-                    {!!onResetColor && cal.colorIsLocalOverride && (
+                    {!!onResetColor && cal.isShared && cal.colorIsLocalOverride && (
                       <Pressable
                         onPress={() => { onExpand(null); onResetColor(cal); }}
                         style={({ pressed }) => [styles.panelRow, pressed && styles.rowPressed]}
@@ -277,6 +334,33 @@ function Section({
                     )}
                   </>
                 )}
+                {canShare && (
+                  <Pressable
+                    onPress={() => { onExpand(null); onShare!(cal); }}
+                    style={({ pressed }) => [styles.panelRow, pressed && styles.rowPressed]}
+                  >
+                    <Share2 size={16} color={c.textSecondary} />
+                    <Text style={styles.panelRowText}>Share…</Text>
+                  </Pressable>
+                )}
+                {canClear && (
+                  <Pressable
+                    onPress={() => { onExpand(null); onClear!(cal); }}
+                    style={({ pressed }) => [styles.panelRow, pressed && styles.rowPressed]}
+                  >
+                    <Eraser size={16} color={c.textSecondary} />
+                    <Text style={styles.panelRowText}>Remove all events</Text>
+                  </Pressable>
+                )}
+                {canDelete && (
+                  <Pressable
+                    onPress={() => { onExpand(null); onDelete!(cal); }}
+                    style={({ pressed }) => [styles.panelRow, pressed && styles.rowPressed]}
+                  >
+                    <Trash2 size={16} color={c.error} />
+                    <Text style={[styles.panelRowText, { color: c.error }]}>Delete calendar</Text>
+                  </Pressable>
+                )}
               </View>
             )}
           </View>
diff --git a/src/components/calendar/ICalSubscriptionSheet.tsx b/src/components/calendar/ICalSubscriptionSheet.tsx
index 495eeee5..e0efcc7e 100644
--- a/src/components/calendar/ICalSubscriptionSheet.tsx
+++ b/src/components/calendar/ICalSubscriptionSheet.tsx
@@ -9,7 +9,20 @@ import Button from '../Button';
 import { spacing, radius, typography, type ThemePalette } from '../../theme/tokens';
 import { useColors } from '../../theme/colors';
 import { CALENDAR_COLOR_PALETTE } from '../../lib/calendar-utils';
-import { useCalendarSubscriptionsStore } from '../../stores/calendar-subscriptions-store';
+import {
+  DEFAULT_REFRESH_INTERVAL_MINUTES,
+  selectAccountSubscriptions,
+  useCalendarSubscriptionsStore,
+  type CalendarSubscription,
+} from '../../stores/calendar-subscriptions-store';
+import { jmapClient } from '../../api/jmap-client';
+
+const INTERVAL_OPTIONS: { minutes: number; label: string }[] = [
+  { minutes: 15, label: '15 min' },
+  { minutes: 60, label: '1 h' },
+  { minutes: 360, label: '6 h' },
+  { minutes: 1440, label: '1 day' },
+];
 
 interface Props {
   visible: boolean;
@@ -20,26 +33,54 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
   const insets = useSafeAreaInsets();
-  const subscriptions = useCalendarSubscriptionsStore((s) => s.subscriptions);
+  const allSubscriptions = useCalendarSubscriptionsStore((s) => s.subscriptions);
+  // Only the signed-in account's feeds: a sub created under another account
+  // mirrors into a calendar id that doesn't exist (or collides) here.
+  const subscriptions = React.useMemo(
+    () => selectAccountSubscriptions(allSubscriptions, jmapClient.isConnected ? jmapClient.accountId : null),
+    [allSubscriptions],
+  );
   const syncing = useCalendarSubscriptionsStore((s) => s.syncing);
   const addSubscription = useCalendarSubscriptionsStore((s) => s.addSubscription);
+  const updateSubscription = useCalendarSubscriptionsStore((s) => s.updateSubscription);
   const removeSubscription = useCalendarSubscriptionsStore((s) => s.removeSubscription);
   const syncSubscription = useCalendarSubscriptionsStore((s) => s.syncSubscription);
 
   const [name, setName] = React.useState('');
   const [url, setUrl] = React.useState('');
   const [color, setColor] = React.useState<string>(CALENDAR_COLOR_PALETTE[0]);
+  const [interval, setInterval] = React.useState<number>(DEFAULT_REFRESH_INTERVAL_MINUTES);
+  const [editingId, setEditingId] = React.useState<string | null>(null);
   const [adding, setAdding] = React.useState(false);
   const [formError, setFormError] = React.useState<string | null>(null);
 
+  const startEdit = (sub: CalendarSubscription) => {
+    setEditingId(sub.id);
+    setName(sub.name);
+    setUrl(sub.url);
+    setColor(sub.color || CALENDAR_COLOR_PALETTE[0]);
+    setInterval(sub.refreshIntervalMinutes ?? DEFAULT_REFRESH_INTERVAL_MINUTES);
+    setFormError(null);
+  };
+  const resetForm = () => {
+    setEditingId(null);
+    setName('');
+    setUrl('');
+    setColor(CALENDAR_COLOR_PALETTE[0]);
+    setInterval(DEFAULT_REFRESH_INTERVAL_MINUTES);
+    setFormError(null);
+  };
+
   const slideY = React.useRef(new Animated.Value(900)).current;
   const overlayOpacity = React.useRef(new Animated.Value(0)).current;
 
   React.useEffect(() => {
     if (visible) {
+      setEditingId(null);
       setName('');
       setUrl('');
       setColor(CALENDAR_COLOR_PALETTE[0]);
+      setInterval(DEFAULT_REFRESH_INTERVAL_MINUTES);
       setFormError(null);
       Animated.parallel([
         Animated.timing(slideY, { toValue: 0, duration: 240, easing: Easing.out(Easing.cubic), useNativeDriver: true }),
@@ -53,27 +94,26 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
     }
   }, [visible, slideY, overlayOpacity]);
 
-  const handleAdd = async () => {
+  const handleSubmit = async () => {
     const n = name.trim();
     const u = url.trim();
     if (!n || !u) {
       setFormError('Enter a name and a feed URL.');
       return;
     }
-    if (!/^(https?|webcal):\/\//i.test(u)) {
-      setFormError('URL must start with https://, http:// or webcal://');
+    if (!/^(https?|webcals?):\/\//i.test(u)) {
+      setFormError('URL must start with https://, http://, webcal:// or webcals://');
       return;
     }
     setFormError(null);
     setAdding(true);
     try {
-      const sub = await addSubscription({ name: n, url: u, color });
-      if (sub.lastError) {
-        setFormError(sub.lastError);
+      if (editingId) {
+        await updateSubscription(editingId, { name: n, url: u, color, refreshIntervalMinutes: interval });
       } else {
-        setName('');
-        setUrl('');
+        await addSubscription({ name: n, url: u, color, refreshIntervalMinutes: interval });
       }
+      resetForm();
     } catch (e) {
       setFormError(e instanceof Error ? e.message : 'Could not add subscription.');
     } finally {
@@ -97,7 +137,7 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
           </View>
 
           <ScrollView style={{ flex: 1 }} contentContainerStyle={styles.scroll}>
-            <Text style={styles.sectionLabel}>Add a feed</Text>
+            <Text style={styles.sectionLabel}>{editingId ? 'Edit subscription' : 'Add a feed'}</Text>
             <TextInput
               value={name}
               onChangeText={setName}
@@ -128,19 +168,43 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
                 />
               ))}
             </View>
+            <Text style={styles.fieldLabel}>Refresh every</Text>
+            <View style={styles.intervalRow}>
+              {INTERVAL_OPTIONS.map((opt) => {
+                const active = interval === opt.minutes;
+                return (
+                  <Pressable
+                    key={opt.minutes}
+                    onPress={() => setInterval(opt.minutes)}
+                    style={[styles.intervalChip, active && styles.intervalChipActive]}
+                  >
+                    <Text style={[styles.intervalChipText, active && styles.intervalChipTextActive]}>
+                      {opt.label}
+                    </Text>
+                  </Pressable>
+                );
+              })}
+            </View>
             {!!formError && (
               <View style={styles.errorBox}>
                 <AlertTriangle size={16} color={c.error} />
                 <Text style={styles.errorText}>{formError}</Text>
               </View>
             )}
-            <Button
-              onPress={() => { void handleAdd(); }}
-              disabled={adding}
-              icon={adding ? <ActivityIndicator size="small" color={c.primaryForeground} /> : <Plus size={16} color={c.primaryForeground} />}
-            >
-              {adding ? 'Subscribing…' : 'Subscribe'}
-            </Button>
+            <View style={styles.formActions}>
+              {editingId && (
+                <Button variant="outline" onPress={resetForm} disabled={adding}>
+                  Cancel
+                </Button>
+              )}
+              <Button
+                onPress={() => { void handleSubmit(); }}
+                disabled={adding}
+                icon={adding ? <ActivityIndicator size="small" color={c.primaryForeground} /> : <Plus size={16} color={c.primaryForeground} />}
+              >
+                {adding ? (editingId ? 'Saving…' : 'Subscribing…') : editingId ? 'Save changes' : 'Subscribe'}
+              </Button>
+            </View>
 
             {subscriptions.length > 0 && (
               <>
@@ -150,7 +214,7 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
                   return (
                     <View key={sub.id} style={styles.subRow}>
                       <View style={[styles.subSwatch, { backgroundColor: sub.color || c.primary }]} />
-                      <View style={{ flex: 1, minWidth: 0 }}>
+                      <Pressable style={{ flex: 1, minWidth: 0 }} onPress={() => startEdit(sub)}>
                         <Text style={styles.subName} numberOfLines={1}>{sub.name}</Text>
                         <Text style={styles.subMeta} numberOfLines={1}>
                           {sub.lastError
@@ -159,7 +223,7 @@ export function ICalSubscriptionSheet({ visible, onClose }: Props) {
                               ? `Synced ${formatDistanceToNow(sub.lastSyncAt, { addSuffix: true })}`
                               : 'Not synced yet'}
                         </Text>
-                      </View>
+                      </Pressable>
                       <Pressable
                         onPress={() => { void syncSubscription(sub.id); }}
                         hitSlop={6}
@@ -232,6 +296,20 @@ function makeStyles(c: ThemePalette) {
       marginBottom: spacing.sm,
     },
     colorRow: { flexDirection: 'row', flexWrap: 'wrap', gap: spacing.sm, marginBottom: spacing.md },
+    fieldLabel: { ...typography.caption, color: c.textSecondary, marginBottom: spacing.xs },
+    intervalRow: { flexDirection: 'row', flexWrap: 'wrap', gap: spacing.sm, marginBottom: spacing.md },
+    intervalChip: {
+      paddingHorizontal: spacing.md,
+      paddingVertical: 6,
+      borderRadius: radius.full,
+      borderWidth: 1,
+      borderColor: c.border,
+      backgroundColor: c.surface,
+    },
+    intervalChipActive: { backgroundColor: c.primary, borderColor: c.primary },
+    intervalChipText: { ...typography.caption, color: c.text },
+    intervalChipTextActive: { color: c.primaryForeground },
+    formActions: { flexDirection: 'row', justifyContent: 'flex-end', gap: spacing.sm },
     colorDot: { width: 26, height: 26, borderRadius: 13, borderWidth: 2, borderColor: 'transparent' },
     colorDotActive: { borderColor: c.text },
     errorBox: {
diff --git a/src/screens/CalendarScreen.tsx b/src/screens/CalendarScreen.tsx
index 62e02412..b149ca6e 100644
--- a/src/screens/CalendarScreen.tsx
+++ b/src/screens/CalendarScreen.tsx
@@ -1,6 +1,7 @@
 import React from 'react';
 import {
   Alert,
+  AppState,
   View,
   Text,
   StyleSheet,
@@ -52,6 +53,8 @@ import { CalendarSidebarDrawer } from '../components/calendar/CalendarSidebarDra
 import { TasksSheet } from '../components/calendar/TasksSheet';
 import { ICalImportSheet } from '../components/calendar/ICalImportSheet';
 import { ICalSubscriptionSheet } from '../components/calendar/ICalSubscriptionSheet';
+import { CalendarEditSheet, type CalendarEditValues } from '../components/calendar/CalendarEditSheet';
+import { CalendarShareSheet } from '../components/calendar/CalendarShareSheet';
 import {
   applySharedCalendarColors,
   buildEventDayIndex,
@@ -177,6 +180,17 @@ export default function CalendarScreen() {
   const deleteTask = useCalendarStore((s) => s.deleteTask);
   const toggleCalendarVisibility = useCalendarStore((s) => s.toggleCalendarVisibility);
   const setDefaultCalendar = useCalendarStore((s) => s.setDefaultCalendar);
+  const createCalendar = useCalendarStore((s) => s.createCalendar);
+  const updateCalendar = useCalendarStore((s) => s.updateCalendar);
+  const removeCalendar = useCalendarStore((s) => s.removeCalendar);
+  const clearCalendarEvents = useCalendarStore((s) => s.clearCalendarEvents);
+  const shareCalendar = useCalendarStore((s) => s.shareCalendar);
+  // Calendar management sheets (create / edit / share) opened from the drawer.
+  const [calendarEditTarget, setCalendarEditTarget] = React.useState<
+    { mode: 'create' } | { mode: 'edit'; calendar: Calendar } | null
+  >(null);
+  const [shareTarget, setShareTarget] = React.useState<Calendar | null>(null);
+  const syncDueSubscriptions = useCalendarSubscriptionsStore((s) => s.syncDue);
   const storeCalendars = useCalendarStore((s) => s.calendars);
   const taskOnlyCalendarIds = useCalendarStore((s) => s.taskOnlyCalendarIds);
   const hiddenCalendarIds = useCalendarStore((s) => s.hiddenCalendarIds);
@@ -278,6 +292,16 @@ export default function CalendarScreen() {
     void fetchCalendarsAction();
   }, [hydrate, fetchCalendarsAction]);
 
+  // Refresh iCal subscriptions whose interval elapsed: on mount and whenever
+  // the app returns to the foreground (like the webmail's periodic refresh).
+  React.useEffect(() => {
+    void syncDueSubscriptions();
+    const sub = AppState.addEventListener('change', (state) => {
+      if (state === 'active') void syncDueSubscriptions();
+    });
+    return () => sub.remove();
+  }, [syncDueSubscriptions]);
+
   React.useEffect(() => {
     const { after, before } = rangeForView(viewMode, currentDate, calendarFirstDayOfWeek);
     void ensureRange(after.toISOString(), before.toISOString());
@@ -509,6 +533,86 @@ export default function CalendarScreen() {
     }
   }, [refresh]);
 
+  const reportError = React.useCallback(
+    (err: unknown) => {
+      Alert.alert(
+        t('calendar.notifications.event_error', 'Something went wrong'),
+        err instanceof Error ? err.message : undefined,
+      );
+    },
+    [t],
+  );
+
+  const handleCalendarEditSave = React.useCallback(
+    async (values: CalendarEditValues) => {
+      if (!calendarEditTarget) return;
+      if (calendarEditTarget.mode === 'create') {
+        await createCalendar(values.name, values.color, values.description);
+      } else {
+        await updateCalendar(calendarEditTarget.calendar.id, {
+          name: values.name,
+          color: values.color,
+          description: values.description || null,
+        });
+      }
+    },
+    [calendarEditTarget, createCalendar, updateCalendar],
+  );
+
+  const handleSetCalendarColor = React.useCallback(
+    (cal: Calendar, color: string) => {
+      if (cal.isShared) {
+        // Per-viewer recolor (#345): the owner's colour is left alone.
+        setSharedCalendarColor(sharedCalendarColorKey(cal), color);
+        return;
+      }
+      updateCalendar(cal.id, { color }).catch(reportError);
+    },
+    [setSharedCalendarColor, updateCalendar, reportError],
+  );
+
+  const handleClearCalendar = React.useCallback(
+    (cal: Calendar) => {
+      Alert.alert(
+        t('calendar.management.clear_title', 'Remove all events?'),
+        t(
+          'calendar.management.clear_description',
+          'Every event in this calendar will be deleted. Events that also belong to another calendar are only unlinked.',
+        ),
+        [
+          { text: t('common.cancel', 'Cancel'), style: 'cancel' },
+          {
+            text: t('calendar.management.clear_confirm', 'Remove all'),
+            style: 'destructive',
+            onPress: () => { clearCalendarEvents(cal.id).catch(reportError); },
+          },
+        ],
+      );
+    },
+    [t, clearCalendarEvents, reportError],
+  );
+
+  const handleDeleteCalendar = React.useCallback(
+    (cal: Calendar) => {
+      Alert.alert(
+        t('calendar.management.delete_title', 'Delete calendar?'),
+        t(
+          'calendar.management.delete_description',
+          'The calendar and all of its events will be deleted. This cannot be undone.',
+        ),
+        [
+          { text: t('common.cancel', 'Cancel'), style: 'cancel' },
+          {
+            text: t('common.delete', 'Delete'),
+            style: 'destructive',
+            onPress: () => { removeCalendar(cal.id).catch(reportError); },
+          },
+        ],
+      );
+    },
+    [t, removeCalendar, reportError],
+  );
+
   const isSelectedToday = isToday(selectedDate);
 
   return (
@@ -689,13 +793,19 @@ export default function CalendarScreen() {
         onClose={() => setSidebarVisible(false)}
         onImport={() => { setSidebarVisible(false); setImportVisible(true); }}
         onManageSubscriptions={() => { setSidebarVisible(false); setSubscriptionsVisible(true); }}
-        onSetDefault={(cal) => { void setDefaultCalendar(cal.id); }}
-        onSetColor={(cal, color) => setSharedCalendarColor(sharedCalendarColorKey(cal), color)}
+        onCreate={() => { setSidebarVisible(false); setCalendarEditTarget({ mode: 'create' }); }}
+        onSetDefault={(cal) => { setDefaultCalendar(cal.id).catch(reportError); }}
+        onSetColor={handleSetCalendarColor}
         onResetColor={(cal) => {
           // Drop the local override; the auto-assign effect picks a fresh
           // unused color (so it never reverts to a collision).
           removeSharedCalendarColor(sharedCalendarColorKey(cal));
         }}
+        onRename={(cal) => { setSidebarVisible(false); setCalendarEditTarget({ mode: 'edit', calendar: cal }); }}
+        onShare={(cal) => { setSidebarVisible(false); setShareTarget(cal); }}
+        onClear={handleClearCalendar}
+        onDelete={handleDeleteCalendar}
+        isSubscriptionCalendar={isSubscriptionCalendar}
       />
 
       <TasksSheet
@@ -724,6 +834,19 @@ export default function CalendarScreen() {
         visible={subscriptionsVisible}
         onClose={() => setSubscriptionsVisible(false)}
       />
+
+      <CalendarEditSheet
+        visible={!!calendarEditTarget}
+        calendar={calendarEditTarget?.mode === 'edit' ? calendarEditTarget.calendar : null}
+        onSave={handleCalendarEditSave}
+        onClose={() => setCalendarEditTarget(null)}
+      />
+
+      <CalendarShareSheet
+        calendar={shareTarget}
+        onShare={shareCalendar}
+        onClose={() => setShareTarget(null)}
+      />
     </SafeAreaView>
   );
 }
diff --git a/src/stores/__tests__/calendar-subscriptions-store.test.ts b/src/stores/__tests__/calendar-subscriptions-store.test.ts
new file mode 100644
index 00000000..d3afab79
--- /dev/null
+++ b/src/stores/__tests__/calendar-subscriptions-store.test.ts
@@ -0,0 +1,59 @@
+import { describe, it, expect, vi } from 'vitest';
+
+vi.mock('../../api/calendar', () => ({
+  createCalendar: vi.fn(),
+  deleteCalendar: vi.fn(),
+  parseCalendarBlob: vi.fn(),
+  queryEvents: vi.fn(),
+  getEvents: vi.fn(),
+  deleteEvents: vi.fn(),
+  updateEvent: vi.fn(),
+  updateCalendar: vi.fn(),
+}));
+vi.mock('../../api/blob', () => ({ uploadBytes: vi.fn() }));
+vi.mock('../../api/jmap-client', () => ({
+  jmapClient: { accountId: 'acc-1', isConnected: true },
+}));
+vi.mock('../calendar-store', () => ({
+  useCalendarStore: { getState: () => ({}) },
+}));
+vi.mock('@react-native-async-storage/async-storage', () => ({
+  default: {
+    getItem: vi.fn().mockResolvedValue(null),
+    setItem: vi.fn().mockResolvedValue(undefined),
+    removeItem: vi.fn().mockResolvedValue(undefined),
+  },
+}));
+
+import {
+  normalizeFeedUrl,
+  selectAccountSubscriptions,
+  type CalendarSubscription,
+} from '../calendar-subscriptions-store';
+
+describe('normalizeFeedUrl', () => {
+  it('maps webcal:// and webcals:// to https://', () => {
+    expect(normalizeFeedUrl('webcal://example.com/feed.ics').url).toBe('https://example.com/feed.ics');
+    expect(normalizeFeedUrl('WEBCALS://example.com/feed.ics').url).toBe('https://example.com/feed.ics');
+    expect(normalizeFeedUrl('https://example.com/feed.ics').headers).toEqual({});
+  });
+
+  it('moves URL credentials into a basic-auth header (#275)', () => {
+    const { url, headers } = normalizeFeedUrl('https://user:p%40ss@example.com/private.ics');
+    expect(url).toBe('https://example.com/private.ics');
+    expect(headers.Authorization).toBe(`Basic ${Buffer.from('user:p@ss', 'utf8').toString('base64')}`);
+  });
+});
+
+describe('selectAccountSubscriptions', () => {
+  const subs: CalendarSubscription[] = [
+    { id: 'a', name: 'A', url: 'x', calendarId: 'c1', accountId: 'acc-1', lastSyncAt: null, lastError: null },
+    { id: 'b', name: 'B', url: 'y', calendarId: 'c2', accountId: 'acc-2', lastSyncAt: null, lastError: null },
+    { id: 'legacy', name: 'L', url: 'z', calendarId: 'c3', lastSyncAt: null, lastError: null },
+  ];
+
+  it('hides subscriptions that belong to another account, keeping legacy ones', () => {
+    expect(selectAccountSubscriptions(subs, 'acc-1').map((s) => s.id)).toEqual(['a', 'legacy']);
+    expect(selectAccountSubscriptions(subs, 'acc-2').map((s) => s.id)).toEqual(['b', 'legacy']);
+  });
+});
diff --git a/src/stores/calendar-store.ts b/src/stores/calendar-store.ts
index 43bb63c8..f80eb897 100644
--- a/src/stores/calendar-store.ts
+++ b/src/stores/calendar-store.ts
@@ -1,8 +1,13 @@
 import { create } from 'zustand';
 import { persist, createJSONStorage } from 'zustand/middleware';
 import AsyncStorage from '@react-native-async-storage/async-storage';
-import type { Calendar, CalendarEvent, StateChange } from '../api/types';
+import type { Calendar, CalendarEvent, CalendarRights, StateChange } from '../api/types';
 import {
+  type CalendarUpdates,
+  updateCalendar as apiUpdateCalendar,
+  deleteCalendar as apiDeleteCalendar,
+  clearCalendarEvents as apiClearCalendarEvents,
+  setCalendarShare as apiSetCalendarShare,
   getCalendars as fetchCalendars,
   queryEvents,
   getEvents as fetchEvents,
@@ -108,7 +113,11 @@ export interface CalendarState {
     replyTo?: Record<string, string> | null,
   ) => Promise<void>;
   importEvents: (events: Partial<CalendarEvent>[], calendarId: string) => Promise<number>;
-  createCalendar: (name: string, color?: string) => Promise<Calendar>;
+  createCalendar: (name: string, color?: string, description?: string) => Promise<Calendar>;
+  updateCalendar: (id: string, updates: CalendarUpdates) => Promise<void>;
+  removeCalendar: (id: string) => Promise<void>;
+  clearCalendarEvents: (id: string) => Promise<number>;
+  shareCalendar: (id: string, principalId: string, rights: CalendarRights | null) => Promise<void>;
   setDefaultCalendar: (id: string) => Promise<void>;
   // Tasks
   createTask: (task: Partial<CalendarEvent>, calendarId: string) => Promise<void>;
@@ -508,12 +517,52 @@ export const useCalendarStore = create<CalendarState>()(
     return count;
   },
 
-  createCalendar: async (name, color) => {
-    const created = await apiCreateCalendar(name, color);
+  createCalendar: async (name, color, description) => {
+    const created = await apiCreateCalendar(name, color, description);
     set({ calendars: [...get().calendars, created] });
     return created;
   },
 
+  updateCalendar: async (id, updates) => {
+    const cal = get().calendars.find((c) => c.id === id);
+    await apiUpdateCalendar(cal?.originalId || id, updates, cal?.accountId);
+    set({
+      calendars: get().calendars.map((c) => (c.id === id ? { ...c, ...updates } as Calendar : c)),
+    });
+  },
+
+  removeCalendar: async (id) => {
+    const cal = get().calendars.find((c) => c.id === id);
+    await apiDeleteCalendar(cal?.originalId || id, cal?.accountId);
+    set({
+      calendars: get().calendars.filter((c) => c.id !== id),
+      events: get().events.filter((e) => !e.calendarIds?.[id]),
+      tasks: get().tasks.filter((t) => !t.calendarIds?.[id]),
+      hiddenCalendarIds: get().hiddenCalendarIds.filter((x) => x !== id),
+    });
+  },
+
+  clearCalendarEvents: async (id) => {
+    const cal = get().calendars.find((c) => c.id === id);
+    const removed = await apiClearCalendarEvents(cal?.originalId || id, cal?.accountId);
+    await get().refresh();
+    return removed;
+  },
+
+  shareCalendar: async (id, principalId, rights) => {
+    const cal = get().calendars.find((c) => c.id === id);
+    await apiSetCalendarShare(cal?.originalId || id, principalId, rights, cal?.accountId);
+    set({
+      calendars: get().calendars.map((c) => {
+        if (c.id !== id) return c;
+        const next = { ...(c.shareWith ?? {}) };
+        if (rights === null) delete next[principalId];
+        else next[principalId] = rights;
+        return { ...c, shareWith: next };
+      }),
+    });
+  },
+
   setDefaultCalendar: async (id) => {
     const cal = get().calendars.find((c) => c.id === id);
     await apiSetDefaultCalendar(cal?.originalId || id, cal?.accountId);
diff --git a/src/stores/calendar-subscriptions-store.ts b/src/stores/calendar-subscriptions-store.ts
index 2481b1dc..51b04fbe 100644
--- a/src/stores/calendar-subscriptions-store.ts
+++ b/src/stores/calendar-subscriptions-store.ts
@@ -9,7 +9,10 @@ import {
   queryEvents,
   getEvents,
   deleteEvents,
+  updateEvent,
+  updateCalendar,
 } from '../api/calendar';
+import { jmapClient } from '../api/jmap-client';
 import { uploadBytes } from '../api/blob';
 import { useCalendarStore } from './calendar-store';
 
@@ -20,29 +23,88 @@ export interface CalendarSubscription {
   color?: string;
   /** The local Stalwart calendar that mirrors this remote feed. */
   calendarId: string;
+  /** JMAP account the mirror calendar lives in; subs of other accounts are hidden. */
+  accountId?: string;
+  /** Minutes between automatic refreshes (default 60). */
+  refreshIntervalMinutes?: number;
   lastSyncAt: number | null;
   lastError: string | null;
 }
 
+export const DEFAULT_REFRESH_INTERVAL_MINUTES = 60;
+
+// 10 MB is far beyond any real feed; a bigger response is not a calendar.
+const MAX_FEED_BYTES = 10 * 1024 * 1024;
+
 interface SubscriptionsState {
   subscriptions: CalendarSubscription[];
   syncing: Record<string, boolean>;
 
-  addSubscription: (input: { name: string; url: string; color?: string }) => Promise<CalendarSubscription>;
+  addSubscription: (input: {
+    name: string;
+    url: string;
+    color?: string;
+    refreshIntervalMinutes?: number;
+  }) => Promise<CalendarSubscription>;
+  updateSubscription: (
+    id: string,
+    updates: { name?: string; url?: string; color?: string; refreshIntervalMinutes?: number },
+  ) => Promise<void>;
   removeSubscription: (id: string) => Promise<void>;
   syncSubscription: (id: string) => Promise<void>;
   syncAll: () => Promise<void>;
+  /** Refresh every subscription of the active account whose interval elapsed. */
+  syncDue: () => Promise<void>;
 }
 
-// webcal:// is just iCalendar over HTTP(S) — browsers/clients map it to https.
-function normalizeFeedUrl(url: string): string {
-  return url.trim().replace(/^webcal:\/\//i, 'https://');
+/** Subscriptions belonging to the signed-in JMAP account (legacy ones without an accountId count as its own). */
+export function selectAccountSubscriptions(
+  subscriptions: CalendarSubscription[],
+  accountId: string | null,
+): CalendarSubscription[] {
+  return subscriptions.filter((s) => !s.accountId || !accountId || s.accountId === accountId);
+}
+
+function currentAccountId(): string | null {
+  return jmapClient.isConnected ? jmapClient.accountId : null;
+}
+
+// webcal:// and webcals:// are just iCalendar over HTTP(S) — clients map
+// them to https. Credentials embedded in the URL (#275) are moved into an
+// Authorization header because RN's WHATWG fetch rejects userinfo in URLs.
+export function normalizeFeedUrl(url: string): { url: string; headers: Record<string, string> } {
+  let normalized = url.trim().replace(/^webcals?:\/\//i, 'https://');
+  const headers: Record<string, string> = {};
+  const m = /^(https?:\/\/)([^/@]+)@(.+)$/i.exec(normalized);
+  if (m) {
+    const creds = decodeURIComponent(m[2]);
+    normalized = `${m[1]}${m[3]}`;
+    headers.Authorization = `Basic ${base64(creds)}`;
+  }
+  return { url: normalized, headers };
+}
+
+function base64(input: string): string {
+  const g = globalThis as { btoa?: (s: string) => string; Buffer?: { from: (s: string, e: string) => { toString: (e: string) => string } } };
+  if (g.btoa) {
+    // btoa expects latin1; encode UTF-8 bytes first.
+    const bytes = new TextEncoder().encode(input);
+    let bin = '';
+    for (const b of bytes) bin += String.fromCharCode(b);
+    return g.btoa(bin);
+  }
+  if (g.Buffer) return g.Buffer.from(input, 'utf8').toString('base64');
+  return input;
 }
 
 async function fetchAndParseFeed(url: string): Promise<Partial<CalendarEvent>[]> {
-  const res = await fetch(normalizeFeedUrl(url));
+  const { url: feedUrl, headers } = normalizeFeedUrl(url);
+  const res = await fetch(feedUrl, { headers });
   if (!res.ok) throw new Error(`Could not fetch feed (HTTP ${res.status})`);
+  const length = Number(res.headers.get('content-length') || 0);
+  if (length > MAX_FEED_BYTES) throw new Error('Feed is too large');
   const text = await res.text();
+  if (text.length > MAX_FEED_BYTES) throw new Error('Feed is too large');
   if (!/BEGIN:VCALENDAR/i.test(text)) {
     throw new Error('That URL did not return an iCalendar feed');
   }
@@ -52,20 +114,26 @@ async function fetchAndParseFeed(url: string): Promise<Partial<CalendarEvent>[]>
   return events.filter((e) => !!e.start);
 }
 
-// Reconcile the local calendar with the remote feed: delete events whose UID
-// disappeared upstream, then import the current set (importEvents dedupes by
-// UID, so unchanged events are left in place).
+// Reconcile the local calendar with the remote feed: drop events whose UID
+// disappeared upstream (unlinking rather than deleting when the event also
+// lives in another calendar), then import the current set (importEvents
+// dedupes by UID, so unchanged events are left in place).
 async function syncFeedIntoCalendar(calendarId: string, url: string): Promise<void> {
   const parsed = await fetchAndParseFeed(url);
   const parsedUids = new Set(parsed.map((e) => e.uid).filter(Boolean) as string[]);
 
   try {
-    const allIds = await queryEvents([], '', '');
-    const all = allIds.length > 0 ? await getEvents(allIds) : [];
-    const stale = all
-      .filter((e) => e.calendarIds?.[calendarId] && e.uid && !parsedUids.has(e.uid))
-      .map((e) => e.id);
-    if (stale.length > 0) await deleteEvents(stale);
+    const ids = await queryEvents([calendarId], '', '');
+    const existing = ids.length > 0 ? await getEvents(ids) : [];
+    const stale = existing.filter((e) => e.uid && !parsedUids.has(e.uid));
+    const toDelete: string[] = [];
+    for (const e of stale) {
+      const others = { ...(e.calendarIds || {}) };
+      delete others[calendarId];
+      if (Object.keys(others).length === 0) toDelete.push(e.id);
+      else await updateEvent(e.id, { calendarIds: others });
+    }
+    if (toDelete.length > 0) await deleteEvents(toDelete);
   } catch {
     // Non-fatal: if we can't enumerate existing events, still import new ones.
   }
@@ -79,7 +147,7 @@ export const useCalendarSubscriptionsStore = create<SubscriptionsState>()(
       subscriptions: [],
       syncing: {},
 
-      addSubscription: async ({ name, url, color }) => {
+      addSubscription: async ({ name, url, color, refreshIntervalMinutes }) => {
         // Create a dedicated local calendar to hold the feed's events.
         const calendar = await createCalendar(name, color);
         const sub: CalendarSubscription = {
@@ -88,31 +156,55 @@ export const useCalendarSubscriptionsStore = create<SubscriptionsState>()(
           url: url.trim(),
           color,
           calendarId: calendar.id,
+          accountId: currentAccountId() ?? undefined,
+          refreshIntervalMinutes: refreshIntervalMinutes ?? DEFAULT_REFRESH_INTERVAL_MINUTES,
           lastSyncAt: null,
           lastError: null,
         };
-        set({ subscriptions: [...get().subscriptions, sub] });
         // Make the new calendar visible immediately.
         await useCalendarStore.getState().fetchCalendars();
         try {
           set({ syncing: { ...get().syncing, [sub.id]: true } });
           await syncFeedIntoCalendar(sub.calendarId, sub.url);
-          set({
-            subscriptions: get().subscriptions.map((s) =>
-              s.id === sub.id ? { ...s, lastSyncAt: Date.now(), lastError: null } : s,
-            ),
-          });
+          set({ subscriptions: [...get().subscriptions, { ...sub, lastSyncAt: Date.now() }] });
+          await useCalendarStore.getState().refresh();
+          return { ...sub, lastSyncAt: Date.now() };
         } catch (err) {
-          const message = err instanceof Error ? err.message : 'Sync failed';
-          set({
-            subscriptions: get().subscriptions.map((s) =>
-              s.id === sub.id ? { ...s, lastError: message } : s,
-            ),
-          });
+          // Roll back: a bad URL / 404 must not leave a phantom calendar behind.
+          try {
+            await deleteCalendar(calendar.id);
+          } catch {
+            // best-effort
+          }
+          await useCalendarStore.getState().fetchCalendars();
+          throw err instanceof Error ? err : new Error('Sync failed');
         } finally {
           set({ syncing: { ...get().syncing, [sub.id]: false } });
         }
-        return sub;
+      },
+
+      updateSubscription: async (id, updates) => {
+        const sub = get().subscriptions.find((s) => s.id === id);
+        if (!sub) return;
+        const next: CalendarSubscription = {
+          ...sub,
+          ...(updates.name !== undefined ? { name: updates.name.trim() } : {}),
+          ...(updates.url !== undefined ? { url: updates.url.trim() } : {}),
+          ...(updates.color !== undefined ? { color: updates.color } : {}),
+          ...(updates.refreshIntervalMinutes !== undefined
+            ? { refreshIntervalMinutes: updates.refreshIntervalMinutes }
+            : {}),
+        };
+        if (next.name !== sub.name || next.color !== sub.color) {
+          try {
+            await updateCalendar(sub.calendarId, { name: next.name, color: next.color });
+            await useCalendarStore.getState().fetchCalendars();
+          } catch {
+            // The mirror calendar keeps its old name/colour; the sub still updates.
+          }
+        }
+        set({ subscriptions: get().subscriptions.map((s) => (s.id === id ? next : s)) });
+        if (next.url !== sub.url) await get().syncSubscription(id);
       },
 
       removeSubscription: async (id) => {
@@ -132,6 +224,7 @@ export const useCalendarSubscriptionsStore = create<SubscriptionsState>()(
       syncSubscription: async (id) => {
         const sub = get().subscriptions.find((s) => s.id === id);
         if (!sub) return;
+        if (get().syncing[id]) return;
         set({ syncing: { ...get().syncing, [id]: true } });
         try {
           await syncFeedIntoCalendar(sub.calendarId, sub.url);
@@ -153,11 +246,22 @@ export const useCalendarSubscriptionsStore = create<SubscriptionsState>()(
       },
 
       syncAll: async () => {
-        const subs = get().subscriptions;
+        const subs = selectAccountSubscriptions(get().subscriptions, currentAccountId());
         for (const sub of subs) {
           await get().syncSubscription(sub.id);
         }
       },
+
+      syncDue: async () => {
+        if (!jmapClient.isConnected) return;
+        const now = Date.now();
+        const subs = selectAccountSubscriptions(get().subscriptions, currentAccountId());
+        for (const sub of subs) {
+          const interval = (sub.refreshIntervalMinutes ?? DEFAULT_REFRESH_INTERVAL_MINUTES) * 60_000;
+          if (sub.lastSyncAt && now - sub.lastSyncAt < interval) continue;
+          await get().syncSubscription(sub.id);
+        }
+      },
     }),
     {
       name: 'calendar-subscriptions',