frontend/agenda-replan.js

@@ -9,6 +9,10 @@ function createAgendaReplan({ now = () => new Date(), update }) {
     String(date.getMonth() + 1).padStart(2, '0'),
     String(date.getDate()).padStart(2, '0'),
   ].join('-');
+  const dueDay = value => {
+    const match = String(value || '').match(/^(\d{4}-\d{2}-\d{2})(?:$|T)/);
+    return match ? match[1] : '';
+  };
   const current = () => active ? items[index] || null : null;
   const snapshot = () => ({
     active,
@@ -40,7 +44,7 @@ function createAgendaReplan({ now = () => new Date(), update }) {
   return {
     start(overdue) {
       items = (overdue || []).slice().sort((left, right) =>
-        new Date(left.due_date).getTime() - new Date(right.due_date).getTime() ||
+        dueDay(left.due_date).localeCompare(dueDay(right.due_date)) ||
         String(left.repository || '').localeCompare(String(right.repository || '')) ||
         Number(left.number || 0) - Number(right.number || 0)
       );

frontend/dashboard.js

@@ -1524,6 +1524,14 @@
     qs('[data-find-work-estimate]')?.focus();
   }
 
+  function formatCalendarDueDate(value) {
+    const match = String(value || '').match(/^(\d{4})-(\d{2})-(\d{2})(?:$|T)/);
+    if (!match) return '';
+    return new Intl.DateTimeFormat(undefined).format(
+      new Date(Number(match[1]), Number(match[2]) - 1, Number(match[3]))
+    );
+  }
+
   let planTodayTrigger = null;
   function formatPlanMinutes(minutes) {
     if (!Number.isInteger(minutes)) return 'Not set';
@@ -3008,7 +3016,7 @@
       qs('#save-issue-due-date').disabled = false;
       qs('#clear-issue-due-date').disabled = !detail.due_date;
       qs('#issue-due-status').textContent = detail.due_date ?
-        'Due ' + new Date(detail.due_date).toLocaleDateString() : 'No due date set.';
+        'Due ' + formatCalendarDueDate(detail.due_date) : 'No due date set.';
       if (qs('#issue-planning').open && !offlineDetail) loadIssuePlanning();
       if (offlineDetail) {
         setOfflineDetailControls('issue');

frontend/my-work.js

@@ -1,15 +1,26 @@
-function issueDueState(dueDate, now) {
-  if (!dueDate) return null;
-  const due = new Date(dueDate);
-  if (Number.isNaN(due.getTime())) return null;
-  const day = value => value.getFullYear() + '-' + String(value.getMonth() + 1).padStart(2, '0') + '-' +
+function calendarDay(value) {
+  const match = String(value || '').match(/^(\d{4})-(\d{2})-(\d{2})(?:$|T)/);
+  if (!match) return '';
+  const date = new Date(Number(match[1]), Number(match[2]) - 1, Number(match[3]));
+  return date.getFullYear() === Number(match[1]) && date.getMonth() === Number(match[2]) - 1 &&
+    date.getDate() === Number(match[3]) ? match.slice(1, 4).join('-') : '';
+}
+
+function localDay(value) {
+  return value.getFullYear() + '-' + String(value.getMonth() + 1).padStart(2, '0') + '-' +
     String(value.getDate()).padStart(2, '0');
-  const dueDay = day(due);
-  const today = day(now);
+}
+
+function issueDueState(dueDate, now) {
+  const dueDay = calendarDay(dueDate);
+  if (!dueDay) return null;
+  const today = localDay(now);
   if (dueDay < today) return { label: 'Overdue', priority: 2 };
   if (dueDay === today) return { label: 'Due today', priority: 2.5 };
   return {
-    label: 'Due ' + due.toLocaleDateString(undefined, { month: 'short', day: 'numeric' }),
+    label: 'Due ' + new Date(
+      Number(dueDay.slice(0, 4)), Number(dueDay.slice(5, 7)) - 1, Number(dueDay.slice(8, 10))
+    ).toLocaleDateString(undefined, { month: 'short', day: 'numeric' }),
     priority: 4,
   };
 }
@@ -569,18 +580,22 @@ function filterMyWork(items, selectedFilter, selectedMilestone = 'all') {
 
 function agendaMyWork(items, now = new Date()) {
   const start = new Date(now.getFullYear(), now.getMonth(), now.getDate());
-  const tomorrow = new Date(start); tomorrow.setDate(tomorrow.getDate() + 1);
-  const afterTomorrow = new Date(start); afterTomorrow.setDate(afterTomorrow.getDate() + 2);
-  const horizon = new Date(start); horizon.setDate(horizon.getDate() + 7);
+  const today = localDay(start);
+  const tomorrowDate = new Date(start); tomorrowDate.setDate(tomorrowDate.getDate() + 1);
+  const tomorrow = localDay(tomorrowDate);
+  const afterTomorrowDate = new Date(start); afterTomorrowDate.setDate(afterTomorrowDate.getDate() + 2);
+  const afterTomorrow = localDay(afterTomorrowDate);
+  const horizonDate = new Date(start); horizonDate.setDate(horizonDate.getDate() + 7);
+  const horizon = localDay(horizonDate);
   return (items || []).flatMap(item => {
     if (item?.kind !== 'issue' || !item.is_assigned || !item.due_date) return [];
-    const due = new Date(item.due_date);
-    if (Number.isNaN(due.getTime()) || due >= horizon) return [];
-    const group = due < start ? 'Overdue' : due < tomorrow ? 'Today' :
+    const due = calendarDay(item.due_date);
+    if (!due || due >= horizon) return [];
+    const group = due < today ? 'Overdue' : due < tomorrow ? 'Today' :
       due < afterTomorrow ? 'Tomorrow' : 'Next 7 days';
-    return [{ ...item, agenda_group: group, _agenda_due: due.getTime() }];
+    return [{ ...item, agenda_group: group, _agenda_due: due }];
   }).sort((left, right) =>
-    left._agenda_due - right._agenda_due ||
+    left._agenda_due.localeCompare(right._agenda_due) ||
     String(left.repository || '').localeCompare(String(right.repository || '')) ||
     Number(left.number || 0) - Number(right.number || 0)
   ).map(({ _agenda_due, ...item }) => item);

src/push_notifications.py

@@ -306,20 +306,17 @@ async def _dispatch_deadline_reminders_unlocked(
     snapshot = await assigned()
     if snapshot.get("complete") is False:
         return 0
-    due_cutoff = current + timedelta(hours=48)
-    due_count = 0
+    due_days = []
     for item in snapshot.get("items", []):
         if not isinstance(item, dict) or not item.get("due_date"):
             continue
+        raw_due = str(item["due_date"])
         try:
-            due = datetime.fromisoformat(str(item["due_date"]).replace("Z", "+00:00"))
+            due_day = datetime.strptime(raw_due[:10], "%Y-%m-%d").date()
         except ValueError:
             continue
-        if due.tzinfo is None:
-            due = due.replace(tzinfo=timezone.utc)
-        if due <= due_cutoff:
-            due_count += 1
-    if not due_count:
+        due_days.append(due_day)
+    if not due_days:
         return 0
     semaphore = asyncio.Semaphore(max(1, max_concurrency))
 
@@ -335,6 +332,10 @@ async def _dispatch_deadline_reminders_unlocked(
                 or device.delivered_local_day == local_day
             ):
                 return 0
+            local_cutoff = local_now.date() + timedelta(days=2)
+            due_count = sum(due_day <= local_cutoff for due_day in due_days)
+            if not due_count:
+                return 0
             if session_active is not None and not await session_active(device.session_id):
                 await asyncio.to_thread(store.delete_session, device.session_id)
                 return 0

tests/test_deadline_reminders.py

@@ -54,6 +54,36 @@ async def test_deadline_reminder_sends_one_private_local_day_digest_and_deduplic
     assert "private/repo" not in json.dumps(sent)
 
 
+@pytest.mark.anyio
+async def test_deadline_reminder_counts_calendar_days_per_device_timezone(tmp_path):
+    store = PushSubscriptionStore(tmp_path / "push.sqlite3")
+    for device, timezone_name in (("tokyo", "Asia/Tokyo"), ("la", "America/Los_Angeles")):
+        store.upsert(device, {
+            "endpoint": f"https://push.example/{device}",
+            "keys": {"p256dh": "public-key", "auth": "auth-secret"},
+        })
+        store.set_deadline_preferences(device, enabled=True, timezone=timezone_name, reminder_hour=0)
+
+    async def assigned():
+        return {"complete": True, "items": [
+            {"id": 1, "due_date": "2026-08-15T23:59:59Z"},
+            {"id": 2, "due_date": "2026-08-16T23:59:59Z"},
+        ]}
+
+    sent = {}
+    async def send(subscription, payload):
+        device = subscription["endpoint"].rsplit("/", 1)[-1]
+        sent[device] = json.loads(payload)["deadline_count"]
+
+    delivered = await dispatch_deadline_reminders(
+        store, PushConfiguration("public", "private", "mailto:ops@example.com"),
+        assigned, send, now=datetime(2026, 8, 13, 23, 30, tzinfo=timezone.utc),
+    )
+
+    assert delivered == 2
+    assert sent == {"tokyo": 2, "la": 1}
+
+
 @pytest.mark.anyio
 async def test_deadline_reminder_fails_closed_for_incomplete_snapshot_and_before_local_hour(tmp_path):
     store = PushSubscriptionStore(tmp_path / "push.sqlite3")

tests/test_mobile_agenda_replan.py

@@ -83,6 +83,24 @@ run();
     }
 
 
+def test_overdue_replan_orders_by_calendar_day_without_timezone_drift():
+    script = f"""
+const createSweep = require({json.dumps(str(REPLAN))});
+const sweep = createSweep({{update:async()=>({{}})}});
+const started = sweep.start([
+  {{key:'o/r#2',repository:'o/r',number:2,due_date:'2026-08-13T01:00:00Z'}},
+  {{key:'o/r#1',repository:'o/r',number:1,due_date:'2026-08-12T23:59:59Z'}},
+]);
+process.stdout.write(JSON.stringify(started));
+"""
+    environment = {**__import__('os').environ, "TZ": "Asia/Tokyo"}
+    result = subprocess.run(
+        ["node", "-e", script], capture_output=True, text=True, env=environment
+    )
+    assert result.returncode == 0, result.stderr
+    assert json.loads(result.stdout)["current"] == "o/r#1"
+
+
 @pytest.mark.anyio
 async def test_mobile_agenda_exposes_thumb_safe_replan_controls_and_wires_existing_mutation():
     html = await dashboard()

tests/test_my_work.py

@@ -109,6 +109,14 @@ async def test_mobile_batch_planning_can_select_and_clear_active_queue_matches()
     assert "max-width:100%" in html
 
 
+@pytest.mark.anyio
+async def test_issue_sheet_formats_due_date_as_a_calendar_day_without_local_timestamp_conversion():
+    source = await dashboard()
+
+    assert "formatCalendarDueDate(detail.due_date)" in source
+    assert "new Date(detail.due_date).toLocaleDateString()" not in source
+
+
 def test_queue_finder_matches_repository_number_and_title_without_reordering():
     script = f"""
 const work = require({json.dumps(str(MY_WORK))});
@@ -173,6 +181,31 @@ process.stdout.write(JSON.stringify(work.agendaMyWork(items, new Date('2026-08-1
     assert json.loads(result.stdout) == ["a/r#2", "a/r#10", "z/r#1"]
 
 
+@pytest.mark.parametrize("timezone_name", ["Asia/Tokyo", "America/Los_Angeles"])
+def test_mobile_agenda_preserves_the_gitea_calendar_day_in_every_timezone(timezone_name):
+    script = f"""
+const work = require({json.dumps(str(MY_WORK))});
+const now = new Date(2026, 7, 13, 12, 0, 0);
+const built = work({{
+  user:{{login:'timmy'}}, notifications:[], pull_requests:[],
+  issues:[{{number:1,title:'Ship',repository:'o/r',labels:[],assignees:['timmy'],due_date:'2026-08-13T23:59:59Z'}}],
+}}, now);
+process.stdout.write(JSON.stringify({{
+  dueLabel:built[0].due_label,
+  agenda:work.agendaMyWork(built, now).map(item => [item.key, item.agenda_group]),
+}}));
+"""
+    environment = {**os.environ, "TZ": timezone_name}
+    result = subprocess.run(
+        ["node", "-e", script], capture_output=True, text=True, env=environment
+    )
+    assert result.returncode == 0, result.stderr
+    assert json.loads(result.stdout) == {
+        "dueLabel": "Due today",
+        "agenda": [["o/r#1", "Today"]],
+    }
+
+
 def test_agenda_pager_loads_every_issue_page_single_flight_and_retries_failed_page():
     script = f"""
 const work = require({json.dumps(str(MY_WORK))});